a zookeeper must push a stubborn 20 kg penguin across its enclosure. the zookeep
ID: 1491779 • Letter: A
Question
a zookeeper must push a stubborn 20 kg penguin across its enclosure. the zookeeper pushes with a constant force F of 25N parallel to the ground starting the penguin from rest. the first part of the trip d is 8 meters across the ice with a coefficient of kinetic friction .100. the zookeeper stops pushing at point d, friction slows the penguin to a stop distance X2 away from the point d. the second part of the trip is on rougher ice with coefficient of kinetic friction .250.
A) What is the work done by the zookeeper on the penguin?
B) What is the work done by friction along the first section of the trip?
C) Find thr speed vp of the penguin when it reaches distance d.
D) Find the distance X2 during where the penguin slows to a stop.
E) instantaneous rate at which the force of friction does work at point d.
Need it asap!! Thanks so much
Explanation / Answer
A) the work done by the zookeeper on the penguin = 25 * 8 = 200 J
B) the work done by friction along the first section of the trip = (0.1 * 20 * 9.8) * 8
= 156.8 J
C) Here, 200 - 156.8 = 1/2 * 20 * v2
=> 2.078 m/sec ----------------------> speed of the penguin when it reaches distance d
D) Here, 200 - 156.8 = 0.250 * 20 * 9.8 * x2
=> x2 = 0.8816 m ---------------------------> distance X2 during where the penguin slows to a stop
E ) instantaneous rate at which the force of friction does work = F * v
= (0.1 * 20 * 9.8) * 2.078
= 40.728 W
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