Question

Blake and Sandra are having a rummage sale. Blake drags 3 boxes a distance of 10 meters each. He exerts a force of 20 newtons on each box. Sandra drags 4 boxes a distance of 12 meters each. She exerts a force of 15 newtons on each box. Blake takes 2 minutes to complete his work. Sandra takes 4 minutes.

Blake does ____ work than Sandra. Blake’s power ____ is than Sandra’s power.

(Hint: Use W = Fd and P = w/t.)

Answer 1

Blake does less work than Sandra. Blake’s power is

more than Sandra’s power.

Answer 2

For Blake:

3 boxes at a distance of 10 meters each, each box weighs 20 N

Work done by Blake = 3 * 10m * 20N
= 600 J
Power = 600 J/ 2 min
= 300 J/min

For Sandra:

4 boxes, 15 N each at a distance of 12 meters each.

Work done by Sandra = 4 * 15 N *12m
= 720 J
Power = 720 J/ 4 min
= 180 J/min

Blake does less work than Sandra.
Blake's power is more than Sandra's.