You are playing hockey with friends on a very large frozen pond. The hockey puck is at your feet motionless. You take a slap-sho
t with your hockey stick and the hockey puck goes zooming off at a high rate of speed sliding along the ice. The hockey puck eventually comes to a stop because: a. There is no net forward force on the puck and so it will eventually slow down.
b. Friction between the puck and the ice will do enough negative work on the puck to equal the positive work done by you on the puck.
c. Friction between the puck and the ice will do more negative work on the puck than you did positive work on the puck.
d. Friction between the puck and the ice will do less negative work on the puck than you did positive work on the puck.
The correct answer is letter b. Friction between the puck and the ice will do enough negative work on the puck to equal the positive work done by you on the puck.
Explanation:
According to the Newton's First Law of Motion, the rocky puck would keep sliding on the ice forever. However, due to the friction acts on the puck, it will slow down and eventually stopping.
Assuming the light takes essentially no time to reach you, the distance at which the lightning occurred can be calculated by multiplying the speed of sound by the time it takes to hear the thunder:
