An electric pencil sharpener is powered by 6 volts. The current through the pencil sharpener is 0.5 amps. What's is the resistance?
Answer:
Resistance in pencil sharpener = 12 ohms
Explanation:
Given:
Voltage in pencil sharpener = 6 volts
Current in pencil sharpener = 0.5 amps
Find:
Resistance in pencil sharpener
Computation:
Resistance = Voltage / Current
Resistance in pencil sharpener = Voltage in pencil sharpener / Current in pencil sharpener
Resistance in pencil sharpener = 6 / 0.5
Resistance in pencil sharpener = 12 ohms
The image shows street lights powered by solar panels. Which sequence shows the energy transformations taking place in these lights?
A.
gravitational potential energy → vibrational energy → chemical potential energy
B.
radiant energy → chemical potential energy → motion energy
C.
radiant energy → electric energy → radiant energy
D.
sound energy → chemical potential energy → radiant energy
E.
gravitational potential energy → motion energy → radiant energy
Answer:
the answer is c
Explanation:
i did the test
3. Which of the following statements about a scientific theory is wrong?
What are the following statements?
An 16 m tall vase is located 50 m in front of a lens. An image is produced
20 m away from the lens. What is the focal length?
Answer:
f = 14.28 m
Explanation:
Given that,
Object distance, u = -50 m
The image distance from the lens, v = +20 m
We need to find the focal length of the lens. Let the focal length is f. Using the lens formula,
[tex]\dfrac{1}{v}-\dfrac{1}{u}=\dfrac{1}{f}[/tex]
Put all the values,
[tex]\dfrac{1}{20}-\dfrac{1}{(-50)}=\dfrac{1}{f}\\\\f=14.28\ m[/tex]
So, the focal length of the lens is equal to 14.28 m.
Uranium-235 decays to thorium-231 with a half-life of 700 million years. When a rock was formed, it contained 6400 million uranium-235 nuclei and no thorium-231 nuclei. Show that after 2100 million years there are seven times more thorium nuclei than uranium nuclei in the rock.
Answer:
proof in explanation
Explanation:
First, we will calculate the number of half-lives:
[tex]n = \frac{t}{t_{1/2}}[/tex]
where,
n = no. of half-lives = ?
t = total time passed = 2100 million years
[tex]t_{1/2}[/tex] = half-life = 700 million years
Therefore,
[tex]n = \frac{2100\ million\ years}{700\ million\ years}\\\\n = 3[/tex]
Now, we will calculate the number of uranium nuclei left ([tex]n_u[/tex]):
[tex]n_u = \frac{1}{2^{n} }(total\ nuclei)\\\\n_u = \frac{1}{2^{3} }(6400\ million)\\\\n_u = \frac{1}{8}(6400\ million)\\\\n_u = 800\ million[/tex]
and the rest of the uranium nuclei will become thorium nuclei ([tex]u_{th}[/tex])
[tex]n_{th} = total\ nuclei - n_u\\n_{th} = 6400\ million-800\ million\\n_{th} = 5600\ million[/tex]
dividing both:
[tex]\frac{n_{th}}{n_u}=\frac{5600\ million}{800\ million} \\\\n_{th} = 7n_u[/tex]
Hence, it is proven that after 2100 million years there are seven times more thorium nuclei than uranium nuclei in the rock.
An nfl wide reciver can reach a top speed of 10 m/s in only 2.4 seconds. What is the nfl players acceleration
Answer:
The acceleration of the nfl players is 4.167 m/s²
Explanation:
Given;
velocity of the nfl players, v = 10 m/s
time of motion of the nfl players = 2.4 s
Acceleration is the change in velocity with time.
The acceleration of the nfl players is calculated as follows;
a = v/t
where;
a is the acceleration of the nfl players
a = 10 / 2.4
a = 4.167 m/s²
Therefore, the acceleration of the nfl players is 4.167 m/s²
A 90-meter train travels at a constant speed of 10 meters per second. How long will it take to cross a 0.06 bridge?
Answer:
The time taken for the train to cross the bridge is 9.01 s
Explanation:
Given;
length of the train, L₁ = 90 m
length of the bridge, L₂ = 0.06 m
speed of the train, v = 10 m/s
Total distance to be traveled, = L₁ + L₂
= 90 m + 0.06 m
= 90.06 m
Time of motion = Distance / speed
Time of motion = 90.06 / 10
Time of motion = 9.006 s ≅ 9.01 s
Therefore, the time taken for the train to cross the bridge is 9.01 s
When a +0.00235 C charge
moves from point A to point B, its
electric potential energy increases
by 0.418 J. What is the potential
difference between A and B?
Include the correct sign, + or - .
(Unit = V)
Answer:177.87
Explanation:
After going through the hoop, a basketball falls to the floor 3 meters below the hoop. The ball
has a kinetic energy of 17.6 Joules as it strikes the ground. What is the potential energy at the hoop?
Answer:
immma send you the link friend me on hereExplanation:
The Drake Equation The Drake Equation Provides an estimate of how many planets there are in the Solar System that may harbor technically communicative life-forms. Provides an estimate of how many planets there are in our galaxy that may harbor technically communicative life-forms. Provides an estimate of how many planets there are in our galaxy that may harbor life-forms of any kind, no matter how primitive they may be. Provides an estimate of how many planets there are in the Universe that may harbor technically communicative life-forms.
Answer:
Provides an estimate of how many planets there are in our galaxy that may harbor technically communicative life-forms.
Explanation:
A planet can be defined as a large celestial body having sufficient mass to allow for self-gravity and make it assume a nearly circular shape (hydrostatic equilibrium), revolves in an orbit around the Sun in the solar system and has a cleared neighborhood.
Basically, the planets are divided into two (2) main categories and these includes;
I. Outer planets: these planets are beyond the asteroid belt and comprises of jupiter, saturn, uranus and neptune, from left to right of the solar system.
II. Inner planets: these planets are the closest to the sun and comprises of mercury, venus, earth and mars.
These outer planets are made mostly of gases (hydrogen and helium) causing them to be less dense than the solid inner planets. These gases are generally known to be less dense in terms of physical properties.
Some examples of the planet are Mars, Venus, Earth, Mercury, Neptune, Jupiter, Saturn, Uranus, etc.
The Drake equation provides an estimate of how many planets there are in our galaxy that may harbor technically communicative life-forms. It is a probabilistic mathematical expression.
Answer:
The correct answer would be:
B.
the number of communicating civilizations in the cosmos
#PLATOFAM
Have a nice day!
An electric circuit consists of light bulb with resistance of 10.0 ohm is connected to a
voltage source. The source provides a current of 2.00 mA in the bulb. What is the power
of the light bulb?
Answer:
P=I²R
Explanation:
P=2*10^-3 square times 10
4 times ten raise to power minus 5
Question 2 (5 points)
What is the frequency of a sound wave travelling through air at a speed of 340m/s with a wavelength of
1.71m?
Answer:
Frequency of sound wave = 198.83 hertz (Approx.)
Explanation:
Given:
Velocity of sound wave in air = 340 m/s
Wavelength = 1.71 meter
Find:
Frequency of sound wave
Computation:
Frequency = Velocity / Wavelength
Frequency of sound wave = Velocity of sound wave in air / Wavelength
Frequency of sound wave = 340 / 1.71
Frequency of sound wave = 198.8304
Frequency of sound wave = 198.83 hertz (Approx.)
LAST ONE NEED HELP.A car accelerates from rest to 20 m/s, in 5 seconds. The car exerts a force of 6000 N. What is the mass of the car?Single choice.
(2 Points)
1800 kg
1500 kg
1000 kg
900 kg
Answer:
1500kg
Explanation:
Initial velocity(u)=0m/s
Final velocity(v)=20m/s
Time taken=5s
Acceleration=v-u/t
Acceleration=20-0/5=4m/s^2
Force=6000N
Mass=?
Mass=Force/acceleration
= 6000/4
=1500kg
A mother has the genotype Bb for brother green eyes, the months did heterozygous hair, what is the genotype of the father ?
Assuming brown hair (B) color is completely dominant over blond hair (b), then the father's genotype must be bb.
An element in a similar period to carbon would be
A chlorine
B. hydrogen
C. fluorine
D. magnesium
Answer: C: Fluorine
Explanation:
Carbon is in period two on the periodic table of elements. The only other elements in this period are lithium, borilliym, boron, nitrogen, oxygen, flourine, and neon. Therefore, the answer must be C.
State four components of a circuit
Answer:
» Battery or cell
» Switch
» Connecting wires
» Resistor or appliance
Iqbal has push a lighter box and seema has to push a similar heavier box on the same floor . Who will have to apply a larger force and why ?
Answer: Seema
Explanation:
When an object is on the floor, there is a force of friction acting on it. This force is higher if the object is heavier because the object would be pushing against the floor with more force.
To push such an object, one would have to apply enough force to break the friction holding the object to the floor and so with heavier objects, more force is needed to push the object because there is more friction acting on it.
An object is dropped without initial speed
from a height of 20 m above ground and falls
with a constant acceleration of 10 m.s-2.
a. How long does it take the object to
reach the ground?
b. What is its speed upon reaching
ground?
Answer:
a. t = 2 s
b. vf = 20 m/s
Explanation:
a.
We can the second equation of motion to find out the time to reach the ground:
[tex]h = v_it + \frac{1}{2}at^2[/tex]
where,
h = height = 20 m
vi = initial velocity = 0 m/s
t = time taken to reach the ground = ?
a = acceleration = 10 m/s²
Therefore,
[tex]20\ m = (0\ m/s)t+\frac{1}{2} (10\ m/s^2)t^2\\\\t^2 = \frac{20\ m}{5\ m/s^2}\\\\t = \sqrt{4\ s^2}[/tex]
t = 2 s
b.
Here, we will use the first equation of motion to find the final speed:
[tex]v_f = v_i + at\\v_f = 0\ m/s + (10\ m/s^2)(2\ s)[/tex]
vf = 20 m/s
Which is NOT a way to stay safe from static electricity?
a lightning rod on a building
a metal spike in an airport runway
a run through an open field during a lightning storm
an anti-static chain on a large truck
Answer: C is correct :)
Explanation:
Two point charges of +20.0 μC and -8.00 μC are separated by a distance of 20.0 cm. What is the intensity of electric field E midway between these two charges?
Answer:
The intensity of the net electric field will:
[tex]E_{net}=E_{1}+E_{2}=2.52*10^{7}\: N/C[/tex]
Explanation:
Here we need first find the electric field due to the first charge at the midway point.
The electric field equation is given by:
[tex]|E_{1}|=k\frac{q_{1}}{d^{2}}[/tex]
Where:
k is Coulomb's constantq(1) is 20.00 μC or 20*10⁻⁶ Cd is the distance from q1 to the midpoint (d=10.0 cm)So, we will have:
[tex]|E_{1}|=(9*10^{9})\frac{20*10^{-6}}{0.1^{2}}[/tex]
[tex]|E_{1}|=1.8*10^{7}\: N/C[/tex]
The direction of E1 is to the right of the midpoint.
Now, the second electric field is:
[tex]|E_{2}|=k\frac{q_{2}}{d^{2}}[/tex]
[tex]|E_{2}|=(9*10^{9})\frac{8*10^{-6}}{0.1^{2}}[/tex]
[tex]|E_{2}|=7.2*10^{6}\: N/C[/tex]
The direction of E2 is to the right of the midpoint because the second charge is negative.
Finally, the intensity of the net electric field will:
[tex]E_{net}=E_{1}+E_{2}=2.52*10^{7}\: N/C[/tex]
I hope it helps you!
The net electric field midway between these two charges is 2.52 x 10⁷ N/C.
Electric field strengthThe electric field strength between two point charges is the force per unit charge.
Electric field strength due to +20.0 μC charge
[tex]E _1 = \frac{kq_1}{r^2} \\\\E_ 1 = \frac{9 \times 10^9 \times 20 \times 10^{-6}}{(0.1)^2} \\\\E _1 = 18 \times 10^6 \ N/C[/tex]
Electric field strength due to -8μC charge
[tex]E _2 = \frac{kq_2}{r^2} \\\\E_ 2 = \frac{9 \times 10^9 \times 8 \times 10^{-6}}{(0.1)^2} \\\\E _2 = 7.2 \times 10^6 \ N/C[/tex]
The net electric field midway between these two charges is calculated as follows;
[tex]E_{net} = 18 \times 10^6 \ + \ 7.2 \times 10^6\\\\E_{net} = 25.2 \times 10^6 \ N/C\\\\E_{net} = 2.52 \times 10^7 \ N/C[/tex]
Learn more about electric field here: https://brainly.com/question/14372859
A vehicle is travelling with uniform velocity along a straight, level stretch of highway. The combined force due to the rolling friction and air resistance is - 5000 N. What is the applied force on the vehicle as it moves?
Answer:
The applied force on the vehicle is 5,000 N
Explanation:
From the question, we have the following parameters of the motion of the vehicle;
The form of the velocity with which the vehicle is travelling = Uniform velocity
The direction of motion of the vehicle = Along a straight and level stretch of the highway
The combined force which acts as resistance to the vehicle's motion = 5,000 N from rolling friction and resistance of the air opposite to the direction of motion
A vehicle travelling with uniform velocity has zero acceleration, therefore;
The acceleration of the vehicle, a = 0 m/s²
According to Newton's Second Law of Motion, we have;
Force, F = Mass, m × Acceleration, a
∴ The net force of acting on the vehicle, F = m × a
Where;
m = The mass of the vehicle
a = The acceleration of the vehicle = 0 m/s²
∴ F = m × 0 = 0
The net force on the vehicle = 0, therefore;
The applied force + The force of rolling friction and air resistance = 0
We therefore have;
The applied force + 5,000 N = 0
∴ The applied force = 0 - 5,000 N = -5,000 N
The applied force, F = 5,000 N in the direction of motion.
If the impulse applied to an object is 34 Ns when a force Facts on it
for 3 s, then the force acting on it is which of the following?
Answer:
Force = 11.33 Newton
Explanation:
Given the following data;
Impulse = 34 Ns
Time = 3 seconds
To find the force acting on the object;
Impulse = force * time
Substituting into the formula, we have;
34 = force * 3
Force = 34/3
Force = 11.33 Newton
Note: the impulse of an object is equal to the change in momentum experienced by the object.
A ladybug crawls vertically on a leaf. Its motion is shown on the following graph of vertical position y vs. time t. What is the average speed of the ladybug between the times t=4s and t=7s?
0.67 m/s
0 m/s
-0.67 m/s
1.5 m/s
which instrument determine the purity of milk
Answer:
Milk Lactometer
Milk Lactometer: A lactometer is an instrument that is used to check for the purity of milk by measuring its density.
lactometer is used to determine the purity of milk
hope it is helpful to you
Why does it take more force to move a heavy box up a ramp than to move the same box down the ramp?
A.There is more friction on the bottom of the box when going up a ramp.
B.Gravity is pushing the box up the ramp at the same time you are pushing the box up the ramp.
C.When you push an object up a ramp, you are working against atmospheric pressure, which is pushing down.
D.When you push an object up a ramp, you are working against gravity, which pulls the box downward.
relative density of a solid is 2.5 if its volume is 7.5 m³and then find its mass
hope it is helpful to you
need asap!
if the voltage across a 12 ohm resistor is 4.0 volts. the current through the resistor is?
a. 0.33 A.
b. 3.0 A.
c. 48 A.
d. 4.0 A.
Answer:
3.0 A Is the correct option
Explanation:
I = V / R
I = 12/ 4
= 3
NEED HELP A 400 Ω resistor is connected across 200 V. What current will flow?Single choice.
(2 Points)
0.25 A
0.5 A
2.0 A
4.0 A
Answer: 0.5A
Explanation:
According to Ohm's law, the Voltage(V) when a current flows through a resistor can be calculated by using the formula:
V = IR
where,
V = Voltage = 200V
I = current in amps (A)
R = resistance in ohms (Ω) = 400Ω
Current = Voltage / Resistance
I = V/R
I = 200/400
I = 0.5A
Therefore, the current is 0.5 Ampere
A building is 512 m high. What must be the minimum water pressure in a pipe at ground level in order to get water up to a restaurant on the top floor? [3] (Density of water = 1000 kgm-3)
Answer:
The minimum pressure required to get water up to a restaurant on the top floor is 5.0176 x 10⁶ N/m²
Explanation:
Given;
height of the building, h = 512 m
density of water, ρ = 1000 kg/m³
The minimum pressure required to get water up to a restaurant on the top floor is calculated as follows;
P = ρgh
where;
P is the required minimum pressure
g is acceleration due to gravity = 9.8 m/s²
P = 1000 x 9.8 x 512
P = 5.0176 x 10⁶ N/m²
Therefore, the minimum pressure required to get water up to a restaurant on the top floor is 5.0176 x 10⁶ N/m²
When we sit on a chair and study for 2-3 hours, we are not doing work from a physicists point of view. Why?
In the context of physics, work is defined to be the movement of an object when you apply a (pushing or pulling) force.
If you lifted a box to move it upward, then you are doing work. If you slide that box along the floor, then you are also doing work. However, if you try to lift something very heavy, but cannot move it at all, then 0 work is being applied. This is because the object hasn't moved. You need displacement to have work happen.
So that's why a physicist would not consider studying doing "work" (in the context of physics), though I'm sure they would be able to agree that studying does exercise the mind.