Question

HEIp

Answer 1

Four weightlifters (AD) enter a competition. The mass and distance that each lifts are shown in the table.
Weightlifter Mass (kg) Distance (m)
A 100.0 2.25
B 150.0 1.76
C 200.0 1.50
D 250.0 1.25
Which weightlifter does the most work?
(Points : 3)
weightlifter A

weightlifter B

weightlifter C

weightlifter D

Answer 2

Remember that Work=Change in Potential Energy
If the floor is U0, how do you express the potential energy of an object mass M, H meters above the ground?

Answer 3

i don't know...

Answer 4

does mgh sound familiar?

Answer 5

Nope

Answer 6

Have you covered potential energy?

Answer 7

nevermind

Answer 8

I need to go soon. Here's a mini lesson:
Potential energy is the energy in an object held at a "tense" point (like a stretched out spring). We can define any 0 point we like (just like deciding where we want our x and y axes to point), and all other potential energies are defined based on that zero point.
The potential energy of an object above the earth's surface is:
Mass of the object * Acceleration due to gravity * distance from our zero point
(acceleration due to gravity = 9.8m/s^2)
Work is usually expressed as force times distance, yes? but we can also express it as W=change in potential energy.
The weights are at potential=0 to start with and the work done is equal to the potential energy at the given heights.