Momentum Objectives (Mom. and Energy Unit) Define and calculate the momentum of an object.  Determine the impulse given to an object.  Interpret and use force vs. time graphs (Base x Height).  Apply conservation of momentum to solve a variety of problems.  Distinguish between elastic and inelastic collisions. 

Example 2 On a snow-covered road, a car with a mass of 1100 kg collides head- on with a van having a mass of 2500 kg traveling at 8 m/s. As a result of the collision, the vehicles lock together and immediately come to rest. Calculate the speed of the car immediately before the collisions. [Neglect friction]

On a snow-covered road, a car with a mass of 1100 kg collides head-on with a van having a mass of 2500 kg traveling at 8 m/s. As a result of the collision, the vehicles lock together and immediately come to rest. Calculate the speed of the car immediately before the collisions. [Neglect friction] Pbefore (kg*m/s) Pafter (kg*m/s) Car Van Total

Car 1100*Vcar = 1100Vcar Van 2500*(-8) = -20,000 Total On a snow-covered road, a car with a mass of 1100 kg collides head-on with a van having a mass of 2500 kg traveling at 8 m/s. As a result of the collision, the vehicles lock together and immediately come to rest. Calculate the speed of the car immediately before the collisions. [Neglect friction] Pbefore (kg*m/s) Pafter (kg*m/s) Car 1100*Vcar = 1100Vcar Van 2500*(-8) = -20,000 Total 1100Vcar – 20,000

Car 1100*Vcar = 1100Vcar Van 2500*(-8) = -20,000 Total On a snow-covered road, a car with a mass of 1100 kg collides head-on with a van having a mass of 2500 kg traveling at 8 m/s. As a result of the collision, the vehicles lock together and immediately come to rest. Calculate the speed of the car immediately before the collisions. [Neglect friction] Pbefore (kg*m/s) Pafter (kg*m/s) Car 1100*Vcar = 1100Vcar Van 2500*(-8) = -20,000 Total 1100Vcar – 20,000

Car 1100*Vcar = 1100Vcar Mv = (1100+2500)(0) = 0 Van On a snow-covered road, a car with a mass of 1100 kg collides head-on with a van having a mass of 2500 kg traveling at 8 m/s. As a result of the collision, the vehicles lock together and immediately come to rest. Calculate the speed of the car immediately before the collisions. [Neglect friction] Pbefore (kg*m/s) Pafter (kg*m/s) Car 1100*Vcar = 1100Vcar Mv = (1100+2500)(0) = 0 Van 2500*(-8) = -20,000 Total 1100Vcar – 20,000

Example 3 A 4-kg rifle fires a 0.02-kg shell with a velocity of 300 m/s. Find the recoil velocity of the rifle.

A 4-kg rifle fires a 0. 02-kg shell with a velocity of 300 m/s A 4-kg rifle fires a 0.02-kg shell with a velocity of 300 m/s. Find the recoil velocity of the rifle. Pbefore (kg*m/s) Pafter (kg*m/s) Rifle Shell Total

A 4-kg rifle fires a 0. 02-kg shell with a velocity of 300 m/s A 4-kg rifle fires a 0.02-kg shell with a velocity of 300 m/s. Find the recoil velocity of the rifle. Pbefore (kg*m/s) Pafter (kg*m/s) Rifle Shell Total

A 4-kg rifle fires a 0. 02-kg shell with a velocity of 300 m/s A 4-kg rifle fires a 0.02-kg shell with a velocity of 300 m/s. Find the recoil velocity of the rifle. Pbefore (kg*m/s) Pafter (kg*m/s) Rifle Mv = (4+0.02)(0) = 0 Shell Total

A 4-kg rifle fires a 0. 02-kg shell with a velocity of 300 m/s A 4-kg rifle fires a 0.02-kg shell with a velocity of 300 m/s. Find the recoil velocity of the rifle. Pbefore (kg*m/s) Pafter (kg*m/s) Rifle 4*Vrecoil Shell (.02)(300) = 6 Total 6 + 4Vrecoil

Questions to go over Conceptual: 7 Calculation: 9, 16