Question

A child is playing on a hill with a cardboard box. The combined mass of child and box is ? = 120 kg. He climbs into box, which is initially at rest, at the top of the hill. The hill is inclined at an angle of 30 degrees with respect to the horizontal. The coefficients of static and kinetic friction between the box and the hill are mu s = 0.4 and mu k = 0.2. Consider that the box (with child inside) has begun to slide down the hill (you can assume that it has been given a brief push to get it started moving). What is the magnitude of the acceleration of the box? b. If the hill is 4 m tall, what is the child’s speed when he reaches the bottom? c. At the bottom of the hill, the ground becomes level (horizontal), but the coefficients of friction do not change. How far does the child slide before he comes to a stop?

          A child is playing on a hill with a cardboard box. The combined mass of child and box is ? = 120 kg. He climbs into box, which is initially at rest, at the top of the hill. The hill is inclined at an angle of 30 degrees with respect to the horizontal. The coefficients of static and kinetic friction between the box and the hill are mu s = 0.4 and mu k = 0.2.
Consider that the box (with child inside) has begun to slide down the hill (you can assume that it has been given a brief push to get it started moving).
What is the magnitude of the acceleration of the box?  b. If the hill is 4 m tall, what is the child’s speed when he reaches the bottom? c. At the bottom of the hill, the ground becomes level (horizontal), but the coefficients of friction do not change. How far does the child slide before he comes to a stop?

Added by Brian L.

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