PRACTICE PASSAGE 4 When Jack has reached the top of the hill, how much work has

Question

PRACTICE PASSAGE 4 When Jack has reached the top of the hill, how much work has he done? A 1. Jack and Jill are running up a hill, at an incline of approximately 30 to the horizontal, along a path that is 450 m long to the top of the hill, as shown in Figure 1. Jack weighs 900 N and Jill is half his size. They are racing to the top of the hill, and Jill runs up in half the time it takes for Jack to scramble up the hill. Their good friend Ty-Mur measures how long it takes for them to get to the top of the hill and clocks in Jack at 3 minutes A)202.5 B) 405 k C)2025 D) 4050 kJ 2. What was Jill's power output going up the hill? A) 1.125 kW B) 2.250kW C) 33.75 kW D) 67.50 kW 9 Figure 1 Jack and Jill's Hill At the top of the hill is a well where they try to fetch a pail of They decide to drop a penny down to check if there is water in into the well and draw up a full bucket. Then they start walking What did Ty-Mur's stopwatch read if he started it wh Jill dropped the penny and stopped it when they hear the splash from the penny she dropped? water. The well is 15 m deep, but Jill cannot see the bottom. 3. the well. Then they lower the 2 L pail using a pulley system A) 0.04s B) 0.08 s C) 1.77 s D) 3.46s back down the hill. Unfortunately, Jack falls when they are almost at the bottom of the hill when they have travelled 440 m from the summit, and he slides down the hill for 6 m before coming to a stop. ill drops the pail and races down after him. She trips just as she gets close to him, and they wind up sliding down the hill ogether with a coefficient of friction of 0.1 coming to a stop 4. How fast was Till running down the hill just be falling onto J ast as they reach the bottom of the hill.

Explanation / Answer

(1)
Work done = Change in Potential Energy
Work done = m*g*h
W = 900 * 450 * sin(30)
W =  202500 J
W = 202.58 KJ
Correct Option:- (A)

(2)
Work done by Jill, W = 900/2 * 450 * sin(30)
W = 101250 J

Time taken by Jill to reach top, t = 3/2 min = 1.5 * 60 = 90s
Power = Work done / time
P = 101250 / 90 W
P = 1125 W
P = 1.125 KW
Correct Option:- (A)

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