Answer:
correct is b 7N
Explanation:
The torque is
Στ = I α
torque
τ = F x R
bold, indicate vectors. The magnitude of torque is
τ = F R sin θ
in this case the angle is 90º so sin 90 = 1
τ = F R
The moment of inertia of a cylinder
I = ½ M R²
substitute
F R = ½ M R² α
F = ½ M R α
reduce to the SI system
R = 7 cm (1m / 100cm) = 0.07 m
calculate
F = ½ 2 0.07 100
F = 7 N
why does the current splits in parallel circuit and why does the voltage remains equal?
Voltage:
It is basically the difference between the charges of the materials on the ends of the Wire
also known as potential difference
It is very similar to the movement of air, it moves from higher density to lower density. in this case, the change in density is the potential difference
So, since voltage is the difference between the charge available on the ends of a wire. Even if the wire splits in parallel circuit, the difference of the charges remains the same
the more the potential difference, the faster electrons will move to the material with lower charge
Current:
Current is the amount of electrons moving through a cross-section of a wire in a period of time
So basically, it is the amount of electrons that move across a given point on a wire in a period of time
If the wire splits, we will have the same amount of electrons moving through as they would if the wire was not split but now, the electrons passing are divided and hence, if we measure the current after the split, we will find that we have a lower current
that's because we have less charge moving through the cross-section of the wire since some of those electrons are moving through a different wire
That's why the current splits in a parallel circuit
A boy of mass 40kg while running develops a momentum of 180Ns. Calculate the velocity of the boy
Answer:
[tex]\boxed {\boxed {\sf v= 4.5 \ m/s}}[/tex]
Explanation:
The formula for momentum is:
[tex]p=mv[/tex]
(p is momentum, m is mass, and v is velocity)
Let's rearrange the formula for velocity, or v.
[tex]\frac{p}{m} =v[/tex]
Velocity can be found by dividing the momentum by the mass.
The momentum is 180 kilograms meter per second. The mass of the boy is 40 kilograms.
[tex]p=180 \ kg*m/s \\m=40 kg[/tex]
Substitute the values into the formula.
[tex]v=\frac{180 \ kg*m/s}{40 \ kg}[/tex]
Divide. Note that the kilograms or "kg" will cancel each other out.
[tex]v=\frac{180 \ m/s}{40 }[/tex]
[tex]v= 4.5 \ m/s[/tex]
The velocity of the boy is 4.5 meters per second.
If a runner travels 60 m in 12 s, his acceleration is *
Will be marked as brainiest!
Answer:
[tex]a=0.834\ m/s^2[/tex]
Explanation:
Given that,
Displacement, d = 60 m
Time, t = 12 s
We need to find the acceleration of the runner. Using second equation of motion as follows :
[tex]d=ut+\dfrac{1}{2}at^2[/tex]
Here, u = 0 (initial velocity = 0)
a is acceleration
[tex]a=\dfrac{2d}{t^2}\\\\a=\dfrac{2\times 60}{(12)^2}\\\\a=0.834\ m/s^2[/tex]
So, the acceleration of the runner is [tex]0.834\ m/s^2[/tex].
A large beaker of water is filled to its rim with water. A block of wood is then carefully lowered into the beaker until the block is floating. In this process, some water is pushed over the edge and collects in a tray. The weight of the water in the tray is:______
a. Greater than the weight of the block.
b. Less than the weight of the block.
c. Equal to the weight of the block.
Answer:
c. Equal to the weight of the block.
Explanation:
We know that when an object floats , the displaced water by the floating body
has weight equal to the weight of the body . In this condition the upthrust becomes equal to the weight of the body .
In the present case the beaker is full to the brim with water . Then the body was made to float into it . While attaining equilibrium in water , it displaces water whose weight must have been equal to its weight . That liquid got spilled over the edge and collected on the tray .
So water collected on the tray must be equal to the weight of the body floating.
A circular disk of radius 2.0 m rotates, starting from rest, with a constant angular acceleration of 20.0 rad/s2. What is the tangential acceleration of a point on the edge of the disk at the instant that its angular speed is 1.0 rev/s?a. 40 m/s2.
b. 79 m/s2.
c. zero m/s2.
d. 120 m/s2.
e. 110 m/s2.
Answer:
Option (a) is correct.
Explanation:
Given that,
The radius of a circular disk, r = 2 m
Angular acceleration, [tex]\alpha =2\ rad/s^2[/tex]
We need to find the tangential acceleration of a point on the edge of the disk at the instant that its angular speed is 1.0 rev/s.
Let a is the tangential acceleration. The relation between the angular acceleration and tengential acceleration. Let it is a.
[tex]a=\alpha r\\\\a=20\times 2\\\\a=40\ m/s^2[/tex]
So, the tangential acceleration is [tex]40\ m/s^2[/tex].
A measuring tape unwinding from a drum of radius r.The center of the drum is not moving; the tape unwinds as its free endis pulled away from the drum. Neglect the thickness of the tape, sothat the radius of the drum can be assumed not to change as the tapeunwinds. In this case, the standard conventions for the angularvelocity omega and for the (translational) velocity v of the end of the tape result in a constraint equation with a positive sign (e.g., if v>0, that is, the tape is unwinding, then \omega > 0 also).Assume that the function x(t) represents the length of tape that has unwound as a function of time. Find θ(t), the angle through which the drum will have rotated, as a function of time. Express your answer (in radians) in terms of x(t) and any other given quantities.Express your answer (in radians) in terms of x(t) and any other given quantities.θ(t)=x(t)/r
Answer:
θ = x / r
Explanation:
This is an exercise that relates the angular and linear quantities, in the statement they indicate the relationship of the speeds
v = w r
Linear and rotational speeds are defined
v = x / t
w =θ / t
let's substitute in the first equation
x / t = (θ / t) r
x = θ r
θ = x / r
It is important to note that the angles must be measured in radians
a. What frequency is received by a person watching an oncoming ambulance moving at 115 km/h and emitting a steady 753 Hz sound from its siren?
b. What frequency does she receive after the ambulance has passed?
Answer:
A)828.8Hz
B)869.2Hz
Explanation:
Here is a complete question;
What frequency is received by a person watching an oncoming ambulance moving at 115 km/h and emitting a steady 753 Hz sound from its siren? Speed of sound is 345m/s
b. What frequency does she receive after the ambulance has passed?
Vs= speed of the ambulance
, We convert to m/s for unit consistency
= 115 km/h= 115km× 1000m/1m × 1hr/3600s= 31.94m/s
Dopler effect is when observed frequency of wave changes with respect to the source or when observed moves relative to transmitting medium can be expressed as
f'=[ (v + vo)/(v- vs)]*f
=[ (v )/(v- vs)]*f
The sign vo and vs depends on vthe direction of the velocity
f= frequency of ambulance siren= 753Hz
v= speed of sound in air= 345m/s
Vo= speed of observer= 0
A) we are to determine the f' of ambulance as heard by person as ambulance approaching.
To find the frequency f' observed by the person we use the expresion below
Then substitute the values
f'=[ (v )/(v- vs)]*f
=[ (345)/(345-31.94)]×753
= 828.8Hz
B)What frequency does she receive after the ambulance has passed?
To find the frequency f' observed by the person we use the expresion below
Then substitute the values
f'=[ (v )/(v + vs)]*f
=[ (345)/(345 + 31.94)]×753
= 869.2Hz
=
which of the following elements is the most reactive? Chlorine Bromine Fluorine Helium
Answer:
Fluorine is the most reactive
Explanation:
Among the halogens, fluorine, chlorine, bromine, and iodine, fluorine is the most reactive one. It forms compounds with all other elements except the noble gases helium (He), neon (Ne) and argon (Ar), whereas stable compounds with krypton (Kr) and xenon (Xe) are formed.
A freshly caught catfish is placed on a spring scale, and it oscillates up and down with a period of 0.19 s. If the spring constant of the scale is 2330 N/m, what is the mass of the catfish?
Answer:
The mass of the catfish is 2.13 kg
Explanation:
Period of oscillation, T = 0.19 s
spring constant, k = 2330 N/m
The period of oscillation of the spring is given by;
[tex]T = 2\pi \sqrt{\frac{m}{k} }\\\\\frac{T}{2\pi} = \sqrt{\frac{m}{k} }\\\\\frac{T^2}{4\pi^2} = \frac{m}{k}\\\\m = \frac{kT^2}{4\pi^2}[/tex]
where;
m is mass of the catfish
substitute the given values and solve for m;
[tex]m = \frac{kT^2}{4\pi^2} \\\\m = \frac{(2330)(0.19)^2}{4\pi^2} \\\\m = 2.13 \ kg[/tex]
Therefore, the mass of the catfish is 2.13 kg
An ideal gas is confined within a closed cylinder at atmospheric pressure (1.013 * 105 Pa) by a piston. The piston moves until the volume of the gas is reduced to one-ninth of the initial volume. What is the final pressure of the gas when its temperature returns to its initial value?
Answer:
[tex]911700\ \text{Pa}[/tex]
Explanation:
[tex]P_1[/tex] = Initial pressure = [tex]1.013\times 10^5\ \text{Pa}[/tex]
[tex]V_1[/tex] = Initial volume
[tex]V_2[/tex]= Final volume = [tex]\dfrac{V_1}{9}\\\Rightarrow \dfrac{V_1}{V_2}=9[/tex]
Temperature is the same in the initial and final state
From the ideal gas law we have
[tex]P_1V_1=P_2V_2\\\Rightarrow P_2=\dfrac{P_1V_1}{V_2}\\\Rightarrow P_2=P_1\times9\\\Rightarrow P_2=1.013\times 10^5\times 9\\\Rightarrow P_2=911700\ \text{Pa}[/tex]
The final pressure of the system is [tex]911700\ \text{Pa}[/tex].
A school bus moves down a road, dropping off students after school. The bus slows down from a speed of 15 meters per second to a full stop over a distance of 55 meters in 11 seconds. What is the average speed, in meters per second, of the school bus while the bus is slowing down? * 3.7 5.0 26 40
Given :
A school bus moves down a road, dropping off students after school.
The bus slows down from a speed of 15 meters per second to a full stop over a distance of 55 meters in 11 seconds.
To Find :
The average speed, in meters per second, of the school bus while the bus is slowing down.
Solution :
Initial velocity, u = 15 m/s.
Distance travelled, d = 55 m.
Time taken, t = 11 s.
Final velocity, v = 0 m/s.
We know, average velocity is given by :
[tex]v_{avg}=\dfrac{distance}{time}\\\\v_{avg}= \dfrac{55}{11}\ m/s\\\\v_{avg}=5 \ m/s[/tex]
Therefore, average velocity is 5 m/s.
Hence, this is the required solution.
true or false the melting of ice cubes is a exothermic reaction
[tex]\huge\boxed{False}[/tex]
_____________________________________ENDOTHERMIC REACTIONS:Endothermic Reaction are those reactions in which the reactants absorb the energy from their surrounding and forms the product.
_____________________________________How to know endothermic reaction?Those changes in which a substance goes from More-ordered state to less-oredered state are endothermic. Where they change from less ordered to more ordered is exothermic.
More ordered means that the movement of vibration of the particles of the substance is less and the are more close to each other. More to less ordered state is given as,
Solid>Liquid>Gas.
_____________________________________Question:In the question it asks about the melting of the ice cube. Ice cube is a solid, and when it will melt, it will change into the liquid water. As we know that, Solid is more ordered and Liquid is less ordered, and The change from more-ordered to less-ordered is endothermic thus the answer is ENDOTHERMIC.
_____________________________________Best Regards,'Borz'which statement is not correct for lamps connected in parallel
Answer:
This question is not complete but the completed question is below
Which statement is not correct for lamps connected in parallel?
A They can be switched on and off separately.
B They will remain bright if another lamp is connected in parallel.
C They share the supply voltage equally between them.
D They still operate if one lamp is removed.
The correct option is A
Explanation:
Lamps connected in series have the same voltage running across each lamp in the connection and will thus have the same brightness if any lamp is added or removed. This property also means they can only be switched on and off by a single switch, hence option A is not correct about lamps connected in parallel.
Lamps connected in a parallel circuit will have the same voltage and different current.
A parallel circuit contains resistors arranged parallel to each other. some basic characteristics of parallel circuit include the following;
the voltage in all the resistors is the samethe current flowing in each resistor is differentV = I₁R₁ + I₂R₂ + I₃R₃ + ---
where;
V is the voltage in the circuitI is the different currentsR is the different resistorsThus, we can that lamps connected in a parallel circuit will have the same voltage and different current.
Learn more about parallel circuit here: https://brainly.com/question/12739827
What preparation is usually needed for a career in physical science?
Answer:
It includes the sciences of chemistry and physics. Most careers in physical science require a 4-year college degree in one of these fields. Some careers require more advanced education as well. For example, an astronaut might have a master's degree or even a doctoral degree.
Explanation:
Answer: i have never seen two pretty best friends.
Explanation:
An object has an average acceleration of +6.07 m/s2 for 0.250 s . At the end of this time the object's velocity is +9.64 m/s .
What was the object's initial velocity?
Answer:
Explanation:
From the question we are given;
Acceleration a = 6.07m/s²
Time t= 0.25s
Final velocity v = 9.64m/s
Required
Initial velocity u
Using the equation of motion
v = u+at
9.64 = u+(6.07)(0.25)
9.64 = u+1.5175
u = 9.64-1.5175
u = 8.1225m/s
Hence the object's initial velocity is 8.1225m/s
BRAINLIEST
Which statement is an assumption that is made about science?
Science is absolute.
The purpose of science is to advance technology.
The universe cannot be understood with certainty.
Science is democratic.
Answer: The purpose of science is to advance technology.
Explanation: My explanation is that science advances things, Such as science made it able to have Siri sand honestly creates what we are using now to type.
The statement "the universe cannot be understood with certainty" is an assumption that is made about science option (C) is correct.
What is science?Science is a rigorous process of acquiring and analyzing information about the earth in the form of testable understandings.
It is given that:
The statements are:
Science is absolute.The purpose of science is to advance technology.The universe cannot be understood with certainty.Science is democratic.As we know; from the definition of science; the rigorous process of acquiring and analyzing information about the earth in the form of testable understandings.
The assumption made about science is the universe cannot be understood with certainty.
Thus, the statement "the universe cannot be understood with certainty" is an assumption that is made about science option (C) is correct.
Learn more about the science here:
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2) What does the specific heat capacity of a material tell you about how easy it is to heat up
that material
Answer:
High specific heat -> takes more energy to raise/lower object's temperature
Low specific heat -> takes less energy to raise/lower object's temperature
Explanation:
The specific heat capacity is the amount of heat required to raise the temperature of something per unit of mass.
A high specific heat value for an object means it takes more energy to raise or lower that object's temperature. A low specific heat value for an object means it does not take very much energy to heat or cool that object.
he gravitational force between two objects of masses m1m1m_1 and m2m2m_2 that are separated by distance rrr is
Answer:
[tex]F = \frac{6.67408m_1 m_2}{10^{11}r^2}[/tex]
Explanation:
Given
[tex]Object_1 = m_1[/tex]
[tex]Object_2 = m_2[/tex]
[tex]Distance = r[/tex]
Required
Determine the force of attraction
This is calculated as:
[tex]F = \frac{GMm}{d^2}[/tex]
Where
M = mass of object 1
m = mass of object 2
d = distance
Where G = gravitational constant
[tex]G = 6.67408 * 10^{-11}\ m^3 kg^{-1} s^{-2}[/tex]
Substitute these values in
[tex]F = \frac{GMm}{d^2}[/tex]
[tex]F = \frac{6.67408 * 10^{-11} * m_1 * m_2}{r^2}[/tex]
[tex]F = \frac{6.67408 * m_1 * m_2* 10^{-11}}{r^2}[/tex]
[tex]F = \frac{6.67408m_1 m_2* 10^{-11}}{r^2}[/tex]
[tex]F = \frac{6.67408m_1 m_2}{10^{11}*r^2}[/tex]
[tex]F = \frac{6.67408m_1 m_2}{10^{11}r^2}[/tex]
If 10 calories of energy are added to 2 grams of ice at -30° C, calculate the final temperature of the ice. (Notice that the specific heat of ice is different from that of water.) Assume the specific heat of ice is 0.5
-30° C
40° C
-20° C
30° C
Answer:
-20°C
Explanation:
The specific heat capacity of ice using the cgs system is 0.5cal/g°C
The enthalpy change is calculated as follows
ΔH=MC∅ where M represents mass C represents specific heat and ∅ represents the temperature change.
10cal = 2g×0.5cal/g°C×∅
∅=10cal/(2g×0.5cal/g°C)
∅=10°C
Final temperature= -30°C+ 10°C= -20°C
Answer:
-20 degrees Celsius
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A model of a helicopter rotor has four blades, each 3.4 m in length from the central shaft to the tip of the blade. The model is rotated in a wind tunnel at 550 rev/min. What is the radial acceleration of the blade tip, expressed as a multiple of the acceleration g due to gravity?
A. (5.72 × 104)g
B. (6.23 × 102)g
C. (1.15 × 103)g
D. (2.25 × 103)g
A circuit has a voltage drop of 54.0 V across a 30.0 o resistor that carries a current of 1.80 A. What is the power used by the resistor? Use P = VI.
Answer:
P = 97.2 W
Explanation:
Given that,
Voltage drop, V = 54 V
The resistance of the resistor, R = 20 Ohms
Current, I = 1.8 A
We need to find the power used by the resistor. The formula used to find the power is given by :
P = VI
Putting all the values,
P = 54 V × 1.8 A
P = 97.2 W
So, the power used by the resistor is 97.2 W.
during a baseball game you are running home and slide into home plate. However you come up short and you are tagged out. Which force stops you from sliding all the way home? a friction b gravity c pull d push
Answer:1 because
Explanation: it’s pointing to the earth and gravity
Pulls things down to earth
An object of mass 3.00 kg, moving with an initial velocity of 5.05 m/s, collides with and sticks to an object of mass 2.76 kg with an initial velocity of -3.66 m/s. Find the final velocity of the composite object.
Answer:
0.752 m/s
Explanation:
m1 = 3.00kg
u1 = 5.05m/s
m2 = 2.76kg
u2 = -3.66m/s
According to the law of conservation of momentum,
m1u1 + m2u2 = (m1+m2)v
3(5.05) + 2.76(-3.66) = (5.05+2.76)v
15.15 - 9.2736 = 7.81v
5.8764 = 7.81v
v = 5.8764/7.81
v = 0.752m/s
Power is the rate at which work is done true or false
Answer:
false
Explanation:
a current of 200 mA through a conductor converts 40 joules of electrical energy into heat in 30 second
s determine the p
otential drop across the conductor
Answer:
V = 6.65 [volt]
Explanation:
First, we must calculate the power by means of the following equation, where the voltage is related to the energy produced or consumed in a given time.
[tex]P=E/t\\P = 40/30\\P = 1.33[s][/tex]
Using the power we can calculate the voltage, by means of the following equation that relates the voltage to the current.
[tex]P=V*I[/tex]
where:
V = voltage [Volts]
I = current = 200 [mA] = 0.2 [A]
[tex]V = 1.33/0.2\\V = 6.65 [volt][/tex]
Calculate the total number of Cl atoms in 150mL of liquid Ccl4 (d=1.589g/mL)
Answer:
The total number of Cl atoms in 150mL of liquid CCl4 is 3.73*10²⁴.
Explanation:
First you must determine the mass of CCL4 present in 150mL of CCl4. Density is a quantity that allows us to measure the amount of mass in a certain volume of a substance, whose expression for its calculation is the quotient between the mass of a body and the volume it occupies:
[tex]density=\frac{mass}{volume}[/tex]
In this case, the density value of d = 1.589 g/mL. Then, being the volume equal to 150 mL, the value of the mass can be calculated as:
mass= density*volume
mass=1.589 g/mL * 150 mL
mass= 238.35 g
Now, being the molar mass of CCl4 154 g/mol, the number of moles that 238.35 g represents is calculated as:
[tex]moles=\frac{238.35 g}{154 \frac{g}{mol} }[/tex]
moles= 1.55
1 mole of the compound CCl4 contains 4 moles of Cl. Then, using a simple rule of three, it is possible to calculate the number of moles of Cl that 1.55 moles of CCl4 contain:
[tex]moles of Cl=\frac{1.55 moles of CCl_{4} *4 moles of Cl}{1 mole of CCl_{4} }[/tex]
moles of Cl= 6.2
Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023*10²³ particles per mole. Avogadro's number applies to any substance. In this case it can be applied as follows: if 1 mole of Cl contains 6.023*10²³ atoms, 6.2 moles of Cl how many atoms does it contain?
[tex]atoms of Cl=\frac{6.2 moles*6.023*10^{23} atoms}{1 mole}[/tex]
atoms of Cl= 3.73*10²⁴
The total number of Cl atoms in 150mL of liquid CCl4 is 3.73*10²⁴.
A satellite in orbit around the Earth has a speed of 8 km/s at a given point of its orbit. If the period is 2 h, what is the altitude at that point?
Answer:
Explanation:
Using the formula;
Speed = Distance/Time
Given
Speed = 8km/s
Time = 2hr
Convert 2hr to secs
1hr = 3600secs
2hr = 2(3600)
2hr = 7200secs
Altitude is the distance
From the formula;
Distance = speed × time
Distance = 8×7200
Distance = 57200km
Hence the altitude at this point is 57,200km
A 20.0 kg box slides up a 12.0 m long incline at an angle of 30.0 degrees with the
horizontal. A force of 150 N is applied to the box to pull it up the incline. The applied
force makes an angle of 10.0 degrees to the incline. The increase in the kinetic energy
of the box is:
Answer:
jus multiply by 69
Explanation:
There is gravitational force on the Earth from the Sun, and a gravitational force on the Sun from the Earth. Which pulls harder?
Answer:
They both pull the same amount. For every force there is an equal and opposite force.
Explanation:
A person stands at the deep end of a swimming pool and looks at his dive mask which is at the bottom of the pool at a depth of 3.19 m. The index of refraction for water is 1.33. At what depth does the person see his dive mask (apparent depth in meters)? Your answer should be a number with three decimal places, do not include the unit.
Answer:
2.398
Explanation:
In order to solve this problem we are required to use the following information and the question expects us to give depth at which theask is seen.
Dn = D x nobservation/n object
This is the formula for apparent depth
Depth = 3.19
The index of refraction for water is 1.33
3.19x1/1.33
= 3.19/1.33
= 2.398m
the person see his dive mask at
2.398m (apparent depth in meters