Momentum
What is the total momentum of a 15 kg child riding on a 2 kg sled at a combined speed of 1.5 m/s?
25.5 (or 26) kg m/s
The Law of Conservation of Momentum states that in a closed system... (finish the statement)
A 40 kg boy rides a bicycle at 5 m/s. The boy crashes into the bushes. Calculate the boy's change in momentum? Show your work.
-200 kg m/s
When momentum is held constant, mass and velocity are ________ related.
inversely (inverse relationship)
True or False. If there is an outside force acting on a collision, the total momentum of the collision is conserved.
Which ball has the greatest momentum? Show your work
Soccer ball: m= 0.40 kg, v = 30 m/s
Baseball: m = 0.10 kg, v = 40 m/s
Bowling ball: m = 5.0 kg, v = 2 m/s
Soccer Ball, 12 kg m/s
A car with an initial momentum of 20,000 kg m/s collides into a truck with an initial momentum of -30,000 kg m/s, what is the total initial momentum?
20,000 + (-30,000) = -10,000 kg m/s
A 40 kg boy rides a bicycle at 5 m/s. The boy crashes into the bushes in 0.0650 seconds. What is the force acting on the boy during the collision? Show your work.
-3077 (or 3076.9) N
As the mass of an object increases while its velocity stays constant, the momentum of the object will ________ because momentum and mass are ________ related.
increase, directly
How do you define change in velocity (Δv)?
vf - vi (final velocity - initial velocity)
A bowling ball is thrown with an initial momentum of 15.9 kg·m/s and a velocity of 3.5 m/s. What is the mass of the ball?
4.54 kg
A car with an initial momentum of 20,000 kg m/s collides into a truck with an initial momentum of -30,000 kg m/s, what is the total final momentum?
initial = -10,000 kg m/s = final
A 0.43 kg soccer ball is kicked from rest with a velocity of 3.5 m/s. If ball is kicked with a force of 2.25 N, how long is the kick?
0.67 seconds
For an object, as the velocity of the object increases, its momentum ___________. This is a(n) ___________ relationship.
increases, direct/directly proportional
A cart is sliding across a track. If its speed is decreasing as it slides, is the momentum being conserved? Why?
No, there is an external force (friction).
A 12,500 kg rocket launches with an initial momentum of 1,000,000 kg·m/s. What is its velocity?
80 m/s
When is momentum not conserved?
When there is an open system with an external force.
A collision has an change in momentum of 10 kg m/s. If the collision has a force of 3,500 N, what is the collision time?
0.0029 (or 0.00286) seconds
As the amount of time spent in a collision increases, the force of the collision will ________.
decrease.
Cart A (2 kg), with an initial velocity of 4 m/s, collides with Cart B (1 kg), with an initial velocity of -2 m/s.
After the collision, the carts stick together with a velocity of 2 m/s.
Was momentum conserved? Show your work
Yes. Momentum = 6 kg m/s
A 60 kg runner is running at a speed of 1.5 m/s. How fast does a 20 kg dog have to run to have the same momentum as the runner?
4.5 m/s
Object A (10 kg) travels at 4 m/s and collides into and sticks to Object B (5 kg) at rest. Both objects continue moving. Will the speed of Object A increase, decrease, or stay the same? Show your work or explain your reasoning.
Object A's speed will decrease. The total mass has increased, so velocity will decrease.
An egg is dropped on a wooden floor, and the egg is broken with a collision time of 0.0040 seconds with a force of 44 N. You fix the setup to add a cushioned landing surface. Provide an example of new data (collision time and force) that could be collected. Explain why that data would make sense.
collision time (t) > 0.0040
force (F) < 44 N
Which is correct?
Statement 1: A larger force on an object causes there to be a shorter time of collision.
Statement 2: A shorter time of collision causes there to be a larger force on an object.
Statement 2
An object has a total momentum of 40 kg m/s. If the object moves at three times the original speed and has half the original mass, what is the new momentum of the object? Show your work
60 kg m/s