Free Response
Which has more momentum:
A) My cat running to catch a mouse
B) A semitruck at a red light
C) A daddy long leg spider scurrying across the floor.
Cat running to catch a mouse
See Slide 14
5 m/s
A .5 kg ball is thrown with an initial velocity of 35 m/s. The ball comes to a stop when a player catches it. If he catches it in .05 seconds, what force did he have to use?
350N
How does wearing a helmet reduce the amount of force a players head receives while playing?
Increases time so Force decrease
See slide 16
-12m/s
A 2.5 kg soccer ball is kicked with an initial velocity of 25 m/s. The ball comes to a stop when it hits a wall, and the impact time is measured to be 0.1 seconds. Calculate the average force exerted on the soccer ball to bring it to a stop.
625 N
Aircrafts move forward at a slower speed than the air that is propelled backwards. Why?
Conservation of momentum
mv=mv
Mass of aircraft greater than mass of air so velocity of aircraft is lower.
A railway car with a mass of 8000kg is moving at 4.7m/s when it crashes into a 12000kg stationary railway car. They stick together and move forward at what speed?
1.88 m/s
A force of 260N acts on a 1.1kg basketball for .33s.
What is the balls change in momentum and velocity?
p=85.8kgm/s
v=78m/s
Divers can jump higher when jumping off of a diving board compared to jumping off of a cement edge. Why?
(hint-think about the time they are touching the board as compared to the cement block)
Alex, a 52-kg skateboarder, throws a .6-kg ball with a speed of 27 m/s in one direction. What is Alex's velocity after the throw?
-.31m/s
Lisa swings a baseball bat, striking a 0.2 kg baseball that is moving at 31 m/s with a force of 320 N. The ball flies off in the other direction with a velocity of 47 m/s. How long was the ball in contact with her bat?
.05s