High School

A box with a mass of 25 kg is lifted to a height of 3 meters in 2 seconds. How much work was done?

A. 735 J
B. 958 J
C. 245 J
D. 75 J

Answer :

Answer:

Explanation:

Work done = force x displacement

force = mass x acceleration (due to gravity)

work done =25 * 9.8 * 3 = 735J

Answer:

735 J

Explanation:

F (force) = ma = mg = 25kg × 9.81m/s² = 245.25N.

we are lifting, so the acceleration is going against Earth's gravity.

the work done to lift it up by 3 m is then

W = F×d = 245.25N×3 m = 735.75 J

the time (2 seconds) does not play a role here.

it would be needed to calculate the power needed to lift 25kg 3 m in 2 seconds :

power = W/t = 735.75/2 = 367.875 watts