At the gym, a man pulls a bar on a machine that works the muscles of the upper back. It takes him 0.5 seconds to raise 30 kilograms of weights a vertical distance of 0.5 meters.
Which of these exerts the same power output? (Estimate g as 10 m/s2.)

A) lifting 25 kilograms a distance of 2.4 meters in 2.0 seconds

B) lifting 45 kilograms a distance of 2.4 meters in 3.0 seconds
C) leg pressing 45 kilograms a distance of 0.5 meters in 0.5 seconds.
D) bench pressing 30 ligrograms a distance of 0.5 meter in 1.5 seconds .
Please help me

When a 5.0kg cart undergoes a 2.2m/s increase in speed, what is the impulse of the cart

One form of energy can be another type of energy. a. created to form b. transformed into c. destroyed and then created to form

To understand the behavior of the electric field at the surface of a conductor, and its relationship to surface charge on the conductor. a conductor is placed in an external electrostatic field. the external field is uniform before the conductor is placed within it. the conductor is completely isolated from any source of current or charge. part a: which of the following describes the electric field inside this conductor? it is in the same direction as the original external field.it is in the opposite direction from that of the original external field.it has a direction determined entirely by the charge on its surface.it is always zero. part b: the charge density inside the conductor is: 0non-zero; but uniformnon-zero; non-uniforminfinite part c: assume that at some point just outside the surface of the conductor, the electric field has magnitude e and is directed toward the surface of the conductor. what is the charge density η on the surface of the conductor at that point? express your answer in terms of e and ϵ0