The engine's efficiency is (35J)/125J) = 28% .
Do you have a different question to ask ?
Friction produces heat hope this helps
Answer: D
Height of marble from ground
Explanation:
From the formula of kinetic energy and potential energy,
K.E = 1/2mv^2
While
P.E = mgh
From all the parameters given from the question. You can see that mass is constant, acceleration due to gravity is also constant.
Independent variable must be a value that can varies.
Since Jack rolled a marble down a ramp and recorded the potential energy and kinetic energy of the marble at different positions on the ramp to see the effects on both energies.
This different position must be the height which will produce an effect on the potential and kinetic energy of the marble.
Independent variable always provides an effect for dependent variable. Which are kinetic energy and potential energy in this case.
Height of marble from ground is the right answer.
The coil is rotated rapidly in the magnetic field.
The magnetic flux linked with the coil changes and thus, an emf is induced which leads to the flow of current .
when the coil rotates and is in a position along the direction of the magnetic field, emf is maximum while when it is perpendicular to the magnetic field,emf is 0.
Thus an ac generator converts mechanical to electrical energy.It works on the principle of electromagnetic induction. The polarity at the supply terminals changes like.. 100 times a second if the frequency is 50 Hz(50 times+ and 50 times - )
hope it helps!
The motion of the light is a uniform motion with constant speed

, therefore we can use the basic relationship between speed, space and time:

(1)
where S is the distance covered and t is the time taken. The light takes t=1.3 s to travel from the moon to Earth, therefore by rearranging eq.(1) we can find the distance between the Moon and the Earth: