Impulse
What is impulse?
Impulse is the product of force and contact time.
Momentum is what in motion?
Inertia
Define momentum
Find the momentum of an object that has a mass of 12 kg and a velocity of 5 m/s
60 mv
What is the formula for momentum?
mv= F x v
A great force for a long period of time gives you a _____ impulse
Large impulse
A young child and a ball are both rolling down a hill. The child weights 4 times the mass of the ball. In what situation would the ball have the same momentum as the child?
4vc=vb
What is an elastic collision?
An elastic collision is when two objects collide and neither object is deformed
What is the impulse of an object that has 4 N of force applied to it over a period of 9 seconds?
Impulse = F x t
Impulse = 36 Ns
A small force for a short period of time gives you a ______ impulse
smaller impulse
Compare two cars. One that has run into a brick wall, and one that has run into a hay stack. Which car undergoes the greatest change in acceleration? Which car would you rather be in and why? Explain in scientific terms.
The car that has run into the brick wall has the greatest change in acceleration.
Because the hay stack allows the car to keep moving, there is a greater time for the impulse, therefore there is less damage.
What is an inelastic collision?
An inelastic collision is where two objects collide to form a singular object.
Suppose the 5 kg fish swims with a velocity of 2 m/s
toward a 1 kg fish swimming away from him at 1 m/s,
swallows him for lunch, and continues swimming. What
will be the velocity of the fish after the collision?
(5kg x 2 m/s) + (1kg x 1 m/s) = (5kg + 1kg) V
10kg m/s + 1kg m/s = (6kg)V
11kg m/s = (6kg)V
V= 1.8 m/s
What is the formula for impulse?
Force x time = Δ(mv)
When the force that produces an impulse acts for twice as much time, the impulse is:
a. not changed
b. increased by four times
c. increased by two times
d. decreased by half
When the speed of an object doubles, its momentum ______
Doubles
Define conservation of momentum
Momentum is neither created nor destroyed, only transferred and changed by newtons second law
Suppose the 5 kg fish is swimming with a velocity of 1
m/s toward an absent-minded 1 kg fish swimming at 4
m/s toward the larger fish. The larger fish gobbles up
the absent-minded fish for lunch and continues
swimming. What will be the velocity of the fish after the collision?
(5kg x 1m/s) + 1kg (- 4m/s) = (5kg + 1kg)V
5kg m/s - 4kg m/s = (6kg)V
1kg m/s = (6kg)V
V = 1/6 m/s
A bullet shot from a gun with a long barrel will emerge with greater speed because it receives a greater
Impulse
Bonus: What would happen to the bullet if the barrel was shorter?
A car and a heavy truck roll down a hill and reach the bottom at the same speed. Compared with the momentum of the car, the momentum of the truck is:
greater than the momentum of the truck
Your friend says that impulse equals
momentum. This statement isn't correct,
and the missing word is:
Change
Suppose the 5 kg fish is swimming with a velocity of 1
m/s toward an absent-minded 1 kg fish at rest. The larger fish gobbles up the absent-minded fish for lunch and continues swimming. What will be the velocity of the fish after the collision?
5kg x 1m/s + 1kg x 0 m/s = (5kg + 1 kg) V
5kg x m/s = (6kg) V
5 x m/s = (6)V
V= 5/6 m/s
What is the equation for the conservation of momentum?
Net mvbefore = Net mvafter