5.) A 2000 N bear slides down a tree at a constant velocity, what is the

upward force on the bear. If the bear slides down with an

acceleration of 2 m/s/s, determine the upward force on the bear.

2000 N

1600 N

Explanation:

Step 1:

It is given that the bear's weight is 2000 N and it slides down the tree with constant velocity. Since it is sliding with constant velocity the overall force on the bear is zero. The weight of the bear acting downward balances the upward force caused due to friction. Hence the upward force equals the weight 2000 N.

Step 2:

It is given that the bear slides down with an acceleration 2 m/sec sq

Weight of the bear = 2000 N

Mass of the bear = 2000/10 (taking g = 10 m/sec sq) = 200 kg

Force = Mass * Acceleration

Hence net force acting downward = 200*2=400 N.

Net force = Weight of bear - Force acting upward on the bear

400 = 2000 - Force acting upward on the bear

Force on the bear acting upward = 2000 - 400 = 1600 N