1. A student lifts his 2.0-kg pet rock 2.8m straight up. He then lets it drop to the ground. Use the Law of Conservation of Energy to calculate how fast the rock will be moving .....
a. half way down
b. just before it hits the ground
2. A 65-kg girl is running with a speed of 2.5 m/s. How much kinetic energy does she have? She grabs on to a rope that is hanging from the ceiling, and swings from the end of the rope. How high off the ground will she swing?
3. How much work must be done to increase the speed of a 12-kg bicycle ridden by a 68-kg rider from 8.2 m/s to 12.7 m/s?
0 answers