Since the displacement is equal to zero, the velocity from 30 to 40s will also be zero.
VelocityVelocity is the distance travelled by a body in a specific direction per time taken. It is measured in meter per second. That is, m/s
Given that a car started its journey at point A. After 30 seconds, the car had reached point B. The car stops at point B for 10 seconds. Then, the car turned around and arrived at point A after 15 seconds. The car stopped at point A for 20 seconds. The car then went on his way and get to the point C after 10 seconds.
To find the velocity from 30 to 40s, we must realize that velocity can also be defined as;
Velocity = displacement / time
The displacement from point A to B and back to A is equal to zero.
Therefore, The velocity from 30 to 40s is also zero.
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Calculate the mass of air of density 1.2kgm-3 in a room of dimensions 8m by 6m by 4m.
Answer:
230.4kg
Explanation:
volume of the room = l× b×h
volume= 8×6×4
volume=192m3
density= mass/volume
hence mass= density × volume
mass= 1.2kgm-3 × 192m3
mass= 230.4kg
Under water, Zachary can hear waves that travel with frequencies up to 15,000 Hz. What is the velocity of sound in water if a wave with this frequency has a wavelength of 1.2 m?
Answer:
18 000 m/ s
Explanation:
speed = wavelength * frequency
speed = 1.2 * 15 000 = 18 000 m/s
Calculate the power of a person that does 8kJ of work in 4 hours
Answer:
0.56 Watt
Explanation:
Work done = 8 kJ = 8000J
Time = 4 hours = 4*60*60s = 14400sec
Power = ?
Formula of Power is,
Power = Work done / Time
Power = 8000/14400
Power = 0.56 Watt
Hence, Power of person is 0.56Watt.
calculate the work done in kilo joules in lifting a mass of 20kg at steady velocity through a vertical height of 20m
Answer:
[tex]\huge\boxed{\sf Work\ done = 4 kJ}[/tex]
Explanation:
Since work done is in the form of potential energy, we will use the formula of potential energy here.
We know that,
P.E. = mghWhere,
m = mass = 20 kg
g = acceleration due to gravity = 10 m/s²
h = vertical height = 20 m
So,
Work done = mghWork done = (20)(10)(20)
Work done = 4000 joules
Work done = 4 kJ
[tex]\rule[225]{225}{2}[/tex]
In a hard disk drive, a constant torque of 14 N⋅m is applied to the magnetic disk when the drive starts recording data. The magnetic disk has a mass of 0.2 kg and radius 2m. Determine the magnitude of the angular acceleration of the disk? [please solve if you know]
The magnitude of the angular acceleration of the magnetic disk is determined as 35 rad/s².
Angular acceleration of the disk
The angular acceleration of the disk is determined from the principle of conservation of angular momentum as follows;
τ = Iα
where;
α is angular acceleration
I is moment of inertia of the disk
I = 0.5MR²
I = 0.5 x 0.2 x 2²
I = 0.4 kgm²
τ = Iα
α = τ/I
α = (14)/(0.4)
α = 35 rad/s²
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What is an object's acceleration if it is moving at 40 m/s and comes to a stop in 5 s?
An object's acceleration if it is moving and comes to a stop in 5 s will be 8 m/s².
What is acceleration?Acceleration is defined as the rate change of velocity with time.
acceleration a = (Δv) / (Δt)
An object is moving with initial velocity u = 40 m/s and it comes to stop, then its final velocity v= 0 m/s.
Time taken for the change in speed t=5s.
The acceleration is given by
a = (40 -0)/ 5
a = 8 m/s²
Thus, the object's acceleration is 8 m/s².
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Maintaining at least a 1-second space margin from the vehicle in front of you not only provides you with visibility, time, and space to help avoid rear-end crashes, but also allows you to steer or brake out of danger at moderate speeds. Select one: True False
Answer:
True -
60 mph = 60 mph * 5280 ft /hr / (3600 sec/hr) = 88 ft/sec
At 60 mph one would travel 88 ft in 1 second
A machine is used to convert heat energy into work energy, and is connected to a cooling system which keeps the machine at a constant temperature. If 2000 kJ of heat energy enter the machine, and the machine performs 700 kJ of work,
how much heat energy must still be removed by the cooling system?
Remember What the law of Conservation of energy says about the total energy before and after a transformation.
The amount of heat energy that must still be removed by the cooling system is 1300 kJ.
Conservation energyThe total energy before and after a transformation must be equal.
Based on this principle, the heat energy that must still be removed by the cooling system is calculated as follows;
Input heat energy = out put heat energy
E = h + w
2000 kJ = h + 700 kJ
1300 kJ = h
Thus, the amount of heat energy that must still be removed by the cooling system is 1300 kJ.
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A roller coaster car moving at a velocity of 30 meters/second has a momentum of 2.5 × 104 kilogram meters/second. what is its mass? a. 85 kilograms b. 8.3 × 102 kilograms c. 7.6 × 102kilograms d. 7.6 × 103 kilograms e. 7.6 × 104 kilograms
The mass of a rollercoaster car moving at a velocity of 30 meters/second and has a momentum of 2.5 × 104 kilogram meters/second is 8.3 × 10²kg.
How to calculate mass?The mass of the roller coaster car can be calculated using the following formula:
P = m × v
Where;
P = momentumm = massv = velocitym = 2.5 × 10⁴ ÷ 30
m = 8.3 × 10²kg
Therefore, the mass of a rollercoaster car moving at a velocity of 30 meters/second and has a momentum of 2.5 × 104 kilogram meters/second is 8.3 × 10²kg.
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Comment on the statement "Sharper the curve, more is the bending."
The direction of the angular velocity of the minute hand of a wall-clock is perpendicular to the wall and directed inwards.
The passenger slides away from the centre of the curve.
The angle θ which a cyclist should make with the vertical while taking a circular turn of radius r with velocity v given by
tan θ = v^2/rg
Sharper the curve, smaller is the radius and greater is the value of 0.
what are magnetic field line??
Answer:
Magnetic field lines are a visual tool used to represent magnetic fields.meaning you cant really see them with out the tool witch magnetic force on a north and south
Hope This Helped
Cool air tends to...
A. Be less dense and flow over warm air.
B. Be lifted up by more dense warm air.
C. Be more dense and flow under warm air.
D. Mix easily with warm air masses.
Answer: C. Be more dense and flow under warm air.
Explanation:
think of a supermarket selling dairy products and when you open the fridge to get the milk, outside the supermarket is hot and inside the fridge is cold ice.
Sheila weighs 60 kg and is riding a bike. Her momentum on the bike is 340 kg • m/s. The bike hits a rock, which stops it completely and throws Sheila forward onto the pavement.
If there is no net force on the system, what is Sheila’s velocity immediately after she is thrown from the bike?
1.8 m/s
2.0 m/s
5.0 m/s
5.7 m/s
From the calculation, Sheila’s velocity immediately after she is thrown from the bike is 5.7 m/s.
What is momentum?Momentum is the product of mass and velocity. We know that the momentum before collision is equal to the momentum after collision.
Hence;
Momentum before collision = 340 kg • m/s.
Momentum after collision = 60v
Thus;
340 kg • m/s = 60v kg • m/s
v = 340 kg • m/s/60 Kg
v = 5.7 m/s
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A ball is dropped and accelerates downwards at a rate of 10m/s^2 for 12 seconds how much will the ball's velocity increase by?
Answer:
120 m/s
Explanation:
acceleration = velocity/time
10m/s^2 = velocity / 12seconds
10*12 = velocity
120m/s = velocity
1750 N irregular beam is hanging horizontally by its ends from the ceiling by two vertical wires (A and B), each 1.25 m long and weighing 0.290 N. The center of gravity of this beam is one-third of the way along the beam from the end where wire A is attached. If you pluck both strings at the same time at the beam, what is the time delay between the arrival of the two pulses at the ceiling
The time delay between the arrival of the two pulses at the ceiling is 2.33 ms.
What is center of gravity?Any object of mass is attracted towards another by point where whole mass is supposed to be concentrated is called center of gravity.
A 1750 N irregular beam is hanging horizontally by its ends from the ceiling by two vertical wires (A and B), each 1.25 m long and weighing 0.290 N.
The center of gravity of this beam is one-third of the way along the beam from the end where wire A is attached.
Taking moments about one end, to find the tension at other end.
Tb X L = WxL/3
here, W is the weight, L is the length of wire and Tb is the tension at point B.
So, Tb = W/3
and
Tb - Ta = W
here, Ta is the tension in end A.
Substitute the values, we get
Tb = 583.33N and Ta = 1166.66N
Velocity of end A, Va = (1166.66 x1.25 x 9.81/0.290 )^(1/2)
Va = 222 m/s
Velocity of end B, Vb = (583.33 x1.25 x 9.81/0.290 )^(1/2)
Va = 157 m/s
Time delay t is related with the velocities as
t = L/Vb - L/Va
Substitute the values, we get
t= 0.00233 s
t = 2.33 ms
Thus, time delay between the arrival of the two pulses at the ceiling is 2.33 ms.
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can someone do this for me please?! Just the answer pls
Problem 2
Answer: Choice D only
Explanation:
Let's go through the list of possible answers
A) She only would feel a force pulling her toward the chair, hence making her feel heavier, only when the space ship is accelerating faster. In this case, she is moving a constant speed of 0.5c (aka half the speed of light). Despite going this fast, she is moving at a constant speed and therefore not accelerating at this current time. The speed isn't changing. Therefore, she would not feel a force pushing her into the chair. Choice A is off the list.B) This is also off the list as well. The lack of accelerating force means her lungs aren't compressed and breathing should be normal. This is assuming she doesn't have any medical conditions hindering her breathing. We can cross choice B off the list.C) This is similar to choice B. We can cross it off the list.D) The faster you go, the more time dilation will occur. This effectively compresses time and makes it slow down. The more detailed explanation involves relativity which is very complicated. Therefore, choice D is the answer.E) This is false because choice D was mentioned to be true.Our Sun has a peak emission wavelength of about 500 nm and a radius of about 700,000 km. Your dark-adapted eye has a pupil diameter of about 7 mm and can detect light intensity down to about 1.5 x 10-11 W/m2. Assume the emissivity of the Sun is equal to 1. First, given these numbers, what is the surface temperature of the Sun in Kelvin to 3 significant digits
The surface temperature of the Sun in Kelvin to 3 significant digits is 0.127 K.
Surface temperature of the Sun
The surface temperature of the sun is determined by using the following equations as shown below;
P/A = σT⁴
I = σT⁴
where;
I is intensity of the light = 1.5 x 10⁻¹¹ W/m²σ is Boltzmann constant = 5.67 x 10⁻⁸ W/m²K⁴T⁴ = I/σ
T⁴ = (1.5 x 10⁻¹¹)/ (5.67 x 10⁻⁸)
T⁴ = 2.65 x 10⁻⁴
T = (2.65 x 10⁻⁴)^¹/₄
T = 0.127 K
Thus, the surface temperature of the Sun in Kelvin to 3 significant digits is 0.127 K.
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Which type of rays have a wavelength shorter than that of visible light?
A.
microwaves
B.
infrared rays
C.
gamma rays
D.
radio waves
Answer:
c
Explanation:
wavelength shorter means energy is higher
the wavelength
radio waves>microwave>infrared rays>gamma rays
Angling of the focal track of the anode to create a large actual focal spot and a smaller effective focal spot describes (the):
Angling of the focal track of the anode to create a large actual focal spot and a smaller effective focal spot describes the line focus principle
What is the line focus principle?
The line focus principle states that as the anode angle is reduced, the actual focal spot also becomes small but the heat loading is increased.
It also explains the relationship between the anode surface and the effective focal spot size.
As a result of this, by angling the target, effective area of the target is made much smaller that the actual area of electron interaction.
Hence, angling of the focal track of the anode to create a large actual focal spot and a smaller effective focal spot describes the line focus principle.
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A boat going from salt water (sg = 1. 03) to fresh water (sg=1. 0) sinks 7. 82cm and after burning 72,730kg of coal rises up by 15. 24cm. Find the original displacement of the boat in seawater in kn
The original displacement of the boat in seawater in km is 7.42 x 10⁻⁵ km.
What is displacement?The shortest path traveled by any particle during its motion.
A boat going from salt water to fresh water sinks 7. 82cm. After burning coal, the boat rises up by 15. 24cm.
Displacement = 15.24 -7.82 = 7.42 cm
1cm = 10⁻⁵ km
So, 7.42 cm =7.42 x 10⁻⁵ km
Thus, the original displacement is 7.42 x 10⁻⁵ km.
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When object 1 came into contact with object 2, object 2 got warmer. what can be concluded about the objects before they came into contact with each other? object 2 did not have thermal energy. object 1 had faster-moving particles. object 1 had less thermal energy. object 2 had fewer particles.
The statement that is true regarding the objects is that object 1 had faster-moving particles, which is option 2. Details about matter can be found below.
What is matter?Matter can be defined as any particle that has weight and occupies space.
Certain particles are present in the different states of matter. According to this question, when object 1 came into contact with object 2, object 2 got warmer.
This suggests that the particles in the object 1 is moving faster due to an increase in temperature.
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Answer: b
Explanation: i took the quiz
how much heat is given off when 210.0g of water at 0 degrees freezes into ice?
In the freezing physical change, when 210.0 g of water a 0 degrees freezes into ice, it gives off 71.0 kJ of heat.
What is freezing?It is a physical change in which liquids give off heat to form solids.
We have 210.0 g of water at 0°C. We can calculate the amount of heat given off when it freezes into ice using the following expression.
Q = ΔH°fus × m
Q = 0.334 kJ/g × 210.0 g = 70.1 kJ
where,
Q is the heat released.ΔH°fus is the latent heat of fusion.m is the mass.In the freezing physical change, when 210.0 g of water a 0 degrees freezes into ice, it gives off 71.0 kJ of heat.
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Which quantity is a vector quantity?
A.
displacement
B.
distance
C.
mass
D.
temperature
E.
volume
Answer:
Displacement...
Explanation:
Displacement is a vector quantity as it have both magnitude and direction...
[tex]...[/tex]
a. displacement is the correct answer
Displacement is a vector quantity
EXPLANATIONDisplacement is a vector quantity because it has both magnitude and direction.
Calculate the work done by a crane of power 80,000W in 60 seconds.
Answer:
48MJ
Explanation:
Formula :
Work done = Power × time
============================================================
Given :
⇒ Power = 80,000 W = 80kW
⇒ Time = 60s
=============================================================
Solving :
⇒ Work done = 80kW × 60s
⇒ Work done = 4800kJ
⇒ Work done = 48MJ (megajoule)
I just need the formula solved
Answer:
55 kg
Explanation:
Formula :
Force = mass × acceleration
=========================================================
Given :
⇒ Force = 220 N
⇒ acceleration = 4 m/s²
===========================================================
Solving :
⇒ 220 N = mass × 4 m/s²
⇒ mass = 220/4
⇒ mass = 55 kg
ditto sound waves espace room answers please I need this urgently
The actual question should be did the sound waves escape room?
Yes they can escape the room
Sound always needs a medium to travel throughIf you close the room form all where that even air can't go outside you will be able to hear no sound coming from room .I want to know what is the pressure of the stratosphere simple numbers
I’m in 6 grade
Answer:
This region of increasing temperatures is the stratosphere, spanning a pressure range from 100 millibars at its base to about 10 millibars at the stratopause, the top of the layer.
Explanation:
How is a simple machine different from a compound machine?
a compound machine is made of several simple machines
the difference is like a tree and a jungle
2 large parallel plates are 2.0 cm apart. the strength of the electric plates between them is 100.0 n/c . what is the difference in the voltage between them?
Hello!
We can use the following equation for the potential difference between two parallel plates given an electric field and separation distance:
[tex]V = Ed[/tex]
V = Potential Difference (? V)
E = Electric field strength (100.0 N/C)
d = distance between places (0.02 m)
Plug in the values and solve.
[tex]V = (100)(0.02) = \boxed{2 V}[/tex]
How does the circuit change when the wire is added? a closed circuit occurs and makes all bulbs turn off. an open circuit occurs and makes all bulbs turn off. a short circuit occurs and makes bulbs 3 and 4 turn off but keeps bulbs 1 and 2 lit. a short circuit occurs and makes bulbs 1 and 2 turn off but keeps bulbs 3 and 4 lit.
The circuit change when a wire is added is, an open circuit occurs and makes all bulbs turn off.
What is a closed circuit?A closed circuit is a type of circuit connection in which the wire connection is complete and current flow occurs, turning the light bulbs on in the process.
What is an open circuit?An open circuit is a type of circuit connection in which the wire connection is incomplete and current cannot flow, turning off the light bulbs.
Thus, the circuit change when the wire is added is, an open circuit occurs and makes all bulbs turn off.
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