Question

A bucket of water of mass 15 kg is pulled at constant velocity up to a platform 40 meters above the ground. This takes 16 minutes, during which time 5 kg of water drips out at a steady rate through a hole in the bottom. Find the work needed to raise the bucket to the platform. (Use g=9.8m/s^2.)

Answer 1

4900 J

Explanation:

The average mass of water raised is ...

(15 kg +(15 -5) kg)/2 = 12.5 kg

The work done to raise it 40 m is ...

W = mgh = (12.5 kg)(9.8 m/s^2)(40 m) = 4900 J