Momentum and Impulse
Momentum can be defined as “mass in motion.”
Momentum = mass * velocity
In physics, the symbol for the quantity momentum is the small case “p”; thus, the above equation can be rewritten as
p = m * v
The standard metric unit of momentum is the kg*m/s.
Momentum is a vector quantity
Impulse = Change in momentum
If an object experiences a force for a specific amount of time it will result the object”s mass either speeds up or slows down, which is a change in momentum.
This force on an object for a specific amount of time is called an Impulse.
Equation: J = F * t
1.A 1,200-kilogram car traveling at 10 meters per secondhits a tree and is brought to rest in 0.10 second. What is the magnitude of the average force acting on the car to bring it to rest? Fnet = -120,000N
2.What is the speed of a 1.0 × 103-kilogram car that has a momentum of 2.0 × 104 kilogram?meters per second east? V = 20 m/s East
3.In the diagram below, a 60-kilogram rollerskater exerts a 10-newton force on a 30-kilogram rollerskater for 0.20 second. What is the magnitude of the impulse applied to the
J = 2 N*s
4.Which situation will produce the greatest change of momentum for a 1.0-kilogram cart?
1. accelerating it from rest to 3.0 m/s
2. accelerating it from 2.0 m/s to 4.0 m/s
3. applying a net force of 5.0 N for 2.0 s
4. applying a net force of 10.0 N for 0.5 s
5.Calculate the magnitude of the impulse applied to a 0.75-kilogram cart to change its velocity from 0.50 meter per second east to 2.00 meters per second east. Change in p = 1.25 Kgm/s
The Law of Momentum Conservation
The total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision.
ELASTIC COLLISION M1 * V1 + M2 * V2 = M1 * V1 + M2 * V2
INELASTIC COLLISION M1 * V1 + M2 * V2 = (M1+M2) * V
6.3000-kg truck moving with a velocity of 10 m/s hits a 1000-kg parked car. The impact causes the 1000-kg car to be set in motion at 15 m/s. Assuming that momentum is conserved during the collision, determine the velocity of the truck after the collision. V = 5m/s
7.At the circus, a 100-kilogram clown is fired 15 meters per second from a 500-kilogram cannon. What is the recoil speed of the cannon?
V2 = -3m/s
8. On a snow-covered road, a car with a mass of 1.1×103 kilograms collides head-on with a van having a mass of 2.5×103 kilograms traveling at 8.0 meters per second. As a result of the collision, the vehicles lock together and immediately come to rest. Calculate the speed of the car immediately before the collision.