Action and Reaction Forces Newton’s Third Law MOMENTUM Action and Reaction Forces Newton’s Third Law

Newton's Third Law of Motion (Law of Action & Reaction) [Law of Forces acting in Pairs]

for every action, there is an equal and opposite reaction. Newton's 3rd Law of Motion says: for every action, there is an equal and opposite reaction. Forces act in pairs. One force is called the action force and the other is called the reaction force.

MOMENTUM Momentum is a property a moving object has because of its mass and velocity.

MOMENTUM Which would hurt more??

MOMENTUM Momentum is a property a moving object has because of its mass and velocity. Momentum can be calculated by : p = mv P = momentum (kgm/s) m = mass (kg) v = velocity (m/s)

MOMENTUM What is the momentum of a 5 kg ball that has a velocity of 15m/s? G F S A/U

Momentum practice problems What is the momentum of a 5 kg ball that has a velocity of 15m/s? G F S A/U P= P P = M V M= 5kg V= 15m/s

Momentum practice problems What is the momentum of a 5 kg ball that has a velocity of 15m/s? G F S A/U P= P P = M V P = 5 x 15 M= 5kg V= 15m/s

Momentum practice problems What is the momentum of a 5 kg ball that has a velocity of 15m/s? G F S A/U P= P P = M V P = 5 x 15 M= 5kg V= 15m/s 75 kg • m/s

MOMENTUM What is the mass of a box that has a momentum of 10 kg • m/s and a velocity of 5m/s? G F S A/U

MOMENTUM What is the mass of a box that has a momentum of 10 kg • m/s and a velocity of 5m/s? G F S A/U P= 10 kg •m/s P = M V M= M V= 5m/s

MOMENTUM What is the mass of a box that has a momentum of 10 kg • m/s and a velocity of 5m/s? G F S A/U P= 10 kg •m/s P = M V M= M V= 5m/s 10 = M x 5

MOMENTUM What is the mass of a box that has a momentum of 10 kg • m/s and a velocity of 5m/s? G F S A/U P= 10 kg •m/s P = M V M= M V= 5m/s 10 = M x 5 10 = M x 5 5 5

MOMENTUM What is the mass of a box that has a momentum of 10 kg • m/s and a velocity of 5m/s? G F S A/U P= 10 kg •m/s P = M V M= M V= 5m/s 10 = M x 5 2 kg 10 = M x 5 5 5

MOMENTUM What is the velocity of a child that has a mass of 20kg and a momentum of 50 kg •m/s ? G F S A/U

MOMENTUM What is the velocity of a child that has a mass of 20kg and a momentum of 50 kg •m/s ? G F S A/U P= 50 kg •m/s P = M V M= 20kg V= V

MOMENTUM What is the velocity of a child that has a mass of 20kg and a momentum of 50 kg •m/s ? G F S A/U P= 50 kg •m/s P = M V M= 20kg V= V 50 = 20 x V

MOMENTUM What is the velocity of a child that has a mass of 20kg and a momentum of 50 kg •m/s ? G F S A/U P= 50 kg •m/s P = M V M= 20kg V= V 50 = 20 x V 20 20

MOMENTUM What is the velocity of a child that has a mass of 20kg and a momentum of 50 kg •m/s ? G F S A/U 5/2 or 2.5 m/s P= 50 kg •m/s P = M V M= 20kg V= V 50 = 20 x V 20 20

Copy this question and the steps to solve Copy this question and the steps to solve! This question is on the assignment, quiz, review and test! If a Miata (900kg) at 30 m/s runs head-on into a Civic (1200kg) and neither car moves after the collision, what is the velocity of the Civic ? Given/ Miata: Miata P = M V Our first job is to find the momentum of the Miata…………

If a Miata (900kg) at 30 m/s runs head-on into a Civic (1200kg) and neither car moves after the collision, what is the velocity of the Civic ? Given/ Miata: Miata: formula P= P P = M V M=900 kg V= 30 m/s Our first job is to find the momentum of the Miata…………

If a Miata (900kg) at 30 m/s runs head-on into a Civic (1200kg) and neither car moves after the collision, what is the velocity of the Civic ? Given/ Miata: Miata: formula SUB P= P P = M V P = 900 x 30 M=900 kg V= 30 m/s Our first job is to find the momentum of the Miata…………

If a Miata (900kg) at 30 m/s runs head-on into a Civic (1200kg) and neither car moves after the collision, what is the velocity of the Civic ? Given/ Miata: Miata: formula SUB ANS/UNITS P= P P = M V P = 900 x 30 P=27000 Kg * m/s M=900 kg V= 30 m/s Since they did NOT move after the collision, their “momentums” must have been EQUAL!

Given/Civic: P = 27,000 kg •m/s If a Miata (900kg) at 30 m/s runs head-on into a Civic (1200kg) and neither car moves after the collision, what is the velocity of the Civic ? Given/ Miata: Miata: formula SUB ANS/UNITS P= P P = M V P = 900 x 30 P=27000 Kg * m/s M=900 kg V= 30 m/s Since they did NOT move after the collision, their “momentums” must have been EQUAL! Given/Civic: P = 27,000 kg •m/s

Given/Civic: P = 27,000 kg •m/s If a Miata (900kg) at 30 m/s runs head-on into a Civic (1200kg) and neither car moves after the collision, what is the velocity of the Civic ? Since they did NOT move after the collision, their “momentums” must have been EQUAL! Given/Civic: P = 27,000 kg •m/s Given/Civic: P = 27,000 kg • m/s M = 1200kg V = V

Given/Civic: P = 27,000 kg •m/s If a Miata (900kg) at 30 m/s runs head-on into a Civic (1200kg) and neither car moves after the collision, what is the velocity of the Civic ? Since they did NOT move after the collision, their “momentums” must have been EQUAL! Given/Civic: P = 27,000 kg •m/s Given/Civic: P = 27,000 kg • m/s M = 1200kg V = V P=mv 27,000 = 1200 x V

Given/Civic: P = 27,000 kg •m/s If a Miata (900kg) at 30 m/s runs head-on into a Civic (1200kg) and neither car moves after the collision, what is the velocity of the Civic ? Since they did NOT move after the collision, their “momentums” must have been EQUAL! Given/Civic: P = 27,000 kg •m/s Given/Civic: P = 27,000 kg • m/s M = 1200kg V = V P=mv 27,000 = 1200 x V V = 22.5 m/s That was the Velocity of the Civic! 1200 1200

The Law of Conservation of Momentum - the total amount of momentum of a group of objects does not change unless outside forces act on the objects. (Ex – momentum of cue ball = momentum of balls struck + remaining momentum in cue ball) What outside force acts against the balls now?

If a larger truck were to run, head to head, into a smaller truck moving at the same speed, what would happen to the momentum of each truck?