Physics Chapter 7 (Momentum)
A 30-kg girl and a 25-kg boy face each other on friction-free roller blades. The girl pushes the boy, who moves away at a speed of 1.0 m/s. The girl's speed is
30Kg V= 25kg 1 m/s = 25/30=.83
What is the average momentum of a 70-kg runner who covers 400 m in 50s?
70kg*(400m/50s)= 560 Kg m/s
After a firecracker falling through the air explodes, the net momentum of its fragments decreases.
False
If the net external force acting on a system is zero, then the total momentum of the system is zero.
False
Impulses are smaller when bouncing takes place.
False
The momentum change of an object is equal to the
Impulse acting on it
If the momentum of an object changes and its mass remains constant
It's velocity is changing, it's accelerating, and there is a force acting on it
If Superman at rest in free space throws an asteroid that has more mass than Superman, then which moves faster?
Superman
Which has more momentum, a large truck moving at 30 miles per hour or a small truck moving at 30 miles per hour?
The large truck
A Ping-Pong ball launcher is fired. Compared to the force on the ball, the force on the launcher is
The same
If a net force acts on a system, the system's momentum will change.
True
The padding on car dashboards lengthens the time of passenger's impact during a collision
True
The cannonball launched from a cannon with a long barrel will be faster because the cannonball receives a greater
impulse
Skelly the skater traveling at high speed needs a certain amount of force to stop him. More stopping force will be needed if he has
more mass, more momentum, and less stopping distance
Compared to a sports car moving at 30 miles per hour, the same sports car moving at 60 miles per hour has
twice as much momentum
