Download Friction worksheet answer key

Forces Worksheet #3 Newton’s Laws Problems
Friction
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1. A box is resting on a flat surface. The box has a mass of 20 kg and a force of 200 N is
pushing the box to the right. The force of friction acting on the box is 100 N to the left.
a. Draw a picture of the box and show all the forces that are acting on the box.
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b. What is the acceleration of the box?
2. A sled is loaded so that it has a weight of 600 N. It is being pulled by sled dogs that are
exerting a force of 200 N to the right. The sled is moving at a constant velocity of 2 rn/s.
a. What is the net force acting on the sled?
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b. What is the coefficient of friction between the sled rails and the snowy surface?
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3. The sled now in #2 accelerates to the right at 4 rn/s
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of the dogs that is now larger than before.
a. What is the frictional force acting on the sled now?
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b. What force must the sleddogs provide now to produce that acceleration?
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The dogs pull so hard that the strap attached to the sled breaks. If the sled was moving at
6 rn/s when the straps broke
c. What acceleration will be acting on the sled now?
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d. How much time will it take for the sled to stop and how far will it travel?
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4 A 1500 kg cai is traveling at 100 km/hr along a flat road surface The car slams on its $*
brakes and starts to slide. If the coefficient of sliding friction is 0.40, how far will the car
travel prior to coming to a complete stop?
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5. A box of old, musty physics books is sitting in the corner of a room. The box has a
mass of 50 kg. The coefficient of static friction between the floor and the box is 0.9.
a. How much force must be used to get the box moving?
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b. How much force must be used to keep the box moving at a constant velocity if the
coefficient of sliding friction is 0 5”
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