A small diamond of mass 10.0 g drops from a swimmer’s earring and falls through the water, reaching a terminal velocity of 2.0 m/s. (a) Assuming the frictional force on the diamond obeys f = −bv, what is b? (b) How far does the diamond fall before it reaches 90 percent of its terminal speed?

A 2.0- kg box is moving at constant speed of 2.0m/s on a frictionless horizontal floor. You apply a horizontal force with a magnitude of 4.0N to make it stop. How long should you apply this force?

Bank robbers have pushed a 1000 kg safe to a third-story floor-toceiling window. They plan to break the window and lower the safe 10.0 m to their truck. Not being too clever, they stack up 500 kg of furniture, tie a rope between the safe and the furniture, and place the rope over a pulley. Then they push the safe out of the window. The coefficient of kinetic friction between the furniture and the floor is 0.5. The rope would break if the force on it exceeds 5000 N. a) Does the rope break? b) What is the acceleration of the safe? c) What is the safe’s speed when it hits the truck?

In the figure, the girl on the sled, weighing 70 lb, leaves point A from rest and goes down a 2% icy slope (assume no friction). She collides with her friend, weighing 60 lb, at point B, 200 feet down the slope. After colliding, they travel together down the slope on the sled. The slope is maintained, but the ice is a little rougher, with a coefficient of friction of μk = 0.15. a) How fast will they be moving immediately after they collide? b) Will they come to a stop after the collision? If so, how far will they travel until they do? If not, what will their acceleration be?