Question

1. A 4-meter plank weighing 8 kg is lying on a dock with 2.71 meters of its length on the dock, and the rest of its length extending off the dock. If a child weighing 61.2 kg walks out onto the part of the plank extending off the dock, what is the maximum distance in meters that the child can walk on the plank from the edge of the dock before he falls into the water?

2. A man pulls a 10-kg sled 68 meters along an angled hill with a force of 84 N, which elevates the man 31 meters above the bottom of the hill. The man then hops on his sled and slides from rest to the bottom of the hill back along his 68 meter path, during which a 149 N frictional force acts upon his sled. How much work in Joules does the man do on the sled in pulling the sled up the hill?

3. A man pulls a 15-kg sled 58 meters along an angled hill with a force of 137 N, which elevates the man 30 meters above the bottom of the hill. The man then hops on his sled and slides from rest to the bottom of the hill back along his 58 meter path, during which a 276 N frictional force acts upon his sled. How much work in Joules does the man do against friction in pulling the sled up the hill?

4. A 83-kg man pulls a 2-kg sled 55 meters along an angled hill with a force of 192 N, which elevates the man 29 meters above the bottom of the hill. The man then hops on his sled and slides from rest to the bottom of the hill back along his 55 meter path, during which a 104 N frictional force acts upon his sled. What is the velocity in m/s of the man on the sled right as he reaches the bottom of the hill?

Answer 1