Aworker pushes a box in a factory. in each case, decide which force has the greater magnitude: the force exerted by the worker on the box or the force exerted by the box on the worker. part athe box is heavy and does not move no matter how hard the worker pushes. a)the force exerted by the worker on the box is greater. b)the magnitudes of the forces are equal. c)the force exerted by the box on the worker is greater. part bsome contents are removed, and now when pushed the box slides across the floor at constant speed. a)the force exerted by the worker on the box is greater. b)the magnitudes of the forces are equal. c)the force exerted by the box on the worker is greater. part cthe worker pushes harder, and the box accelerates. a)the magnitudes of the forces are equal. b)the force exerted by the worker on the box is greater. c)the force exerted by the box on the worker is greater.

Amass m = 74 kg slides on a frictionless track that has a drop, followed by a loop-the-loop with radius r = 18.4 m and finally a flat straight section at the same height as the center of the loop (18.4 m off the ground). since the mass would not make it around the loop if released from the height of the top of the loop (do you know why? ) it must be released above the top of the loop-the-loop height. (assume the mass never leaves the smooth track at any point on its path.) 1. what is the minimum speed the block must have at the top of the loop to make it around the loop-the-loop without leaving the track? 2. what height above the ground must the mass begin to make it around the loop-the-loop? 3. if the mass has just enough speed to make it around the loop without leaving the track, what will its speed be at the bottom of the loop? 4. if the mass has just enough speed to make it around the loop without leaving the track, what is its speed at the final flat level (18.4 m off the ground)? 5. now a spring with spring constant k = 15600 n/m is used on the final flat surface to stop the mass. how far does the spring compress?