True or False
True or False?
The units for momentum are kg/m/s.
False.
The units for momentum are kg*m/s.
If a 70 kg human is walking at 2 m/s, what is her momentum?
a. 130
b. 140
c. 145
d. 150
b. 140
A 400 kg lion is chasing after a buffalo at the speed of 20 m/s. What is the momentum of the lion?
8,000 kg* m/s
What is the formula for momentum?
P= mv
True or False?
The law of conservation of momentum states that the momentum before a collision will always be greater than the momentum after a collision.
False.
Remember,
momentum before collision = momentum after collision
Which of the following objects has the largest momentum?
a. A 500 kg car traveling at 2 m/s
b. A 70 kg person traveling at 5 m/s
c. A 0.5 kg soccer ball traveling at 1 m/s
d. A 5000 kg elephant standing still
A.
P= m*v
P= 500*2
P= 1,000 kg*m/s
A child is running with a speed of 5 m/s. His momentum is 200 kg*m/s. What is the mass of the child?
40 kg
What are the units for mass?
kg
True or False?
If an object is not moving, it has nonzero momentum because it still has mass.
False.
If an object is not moving (velocity= 0) then zero times whatever the mass is will always be zero.
That would mean an object that is not moving would have zero momentum.
A large 700 kg truck is driving with a speed of 20 m/s when it collides with a 300 kg car which is not moving. The two stick together. After the collision, the car and truck will have a speed of:
a. greater than 20 m/s
b. less than 20 m/s
c. exactly equal to 20 m/s
b. less than 20 m/s
This is because they have lost kinetic energy in the collision, but not completely.
A bowler rolls a ball down the lane with a momentum of 40 kg*m/s. It has a mass of 5 kg. What is the speed of the bowling ball?
8 m/s
What are the units for velocity?
m/s
True or False?
It is possible for a small car to have the same momentum as a large truck.
True.
Only if the small car is traveling at a much higher velocity than the large truck.
In which of the following situations would it be possible for a butterfly and a raccoon to have the same momentum?
(There are two correct answers)
a. The butterfly is moving very quickly and the raccoon is moving very slowly.
b. The butterfly is moving very slowly and the raccon is moving very quickly.
c. The butterfly and raccoon are moving with the same velocity.
d. The butterfly and raccoon are both at rest.
a. & d.
If the butterfly has a greater velocity than the raccoon it is possible that it may have the same momentum as the raccoon.
Example:
Butterfly: mass = 0.5 kg velocity = 6 m/s
p = 3 kg*m/s
Raccoon: mass = 6 kg velocity = 0.5 m/s
p = 3 kg*m/s
Also, if both objects (animals) were both at rest, they would have a total momentum of zero, since their velocity equals zero.
rule: anything times zero is zero.
An 80 kg student is running with a speed of 4 m/s.
Find the momentum of the student.
320 kgm/s
Define momentum
True or False?
If they are not moving, an elephant has a larger linear momentum than a lion.
False. Both objects have are moving at a speed of zero.
Their mass times velocity (zero) would equal zero in any case where an object is not moving.
An astronaut is doing a spacewalk when he becomes detached and begins floating away from the space ship. He is holding a large toolbox. What can he do to move back to the space ship. Remember, space is frictionless.
a. Swing the toolbox in cirlces
b. Throw the toolbox towards the space ship so that he will follow it.
c. Swing the toolbox back and forth.
d. Throw the toolbox away from the space ship so that he will move the opposite way.
d.
In the frictionless environment, if he throws the toolbox away from the space ship he will move the opposite way- which is towards the space ship.
A small 200 kg sports car collides with a large 800 kg truck. Before the collision, the sports car was traveling at 25 m/s and the large truck was traveling at 10 m/s in the same direction.
What was the total momentum of the car and truck?
m1v1 + m2v2 = m1v3 + m2v4
13,000 kg*m/s
What is the formula for momentum and define the what the variables stand for
p=mv
p=momentum
m=mass
v=velocity