Download presentation

1
**Impulse, Momentum and Collisions**

AP Physics B

2
IMPULSE AND MOMENTUM The impulse F t is a vector quantity equal in magnitude to the product of the force and the time interval in which it acts. Its direction is the same as that of the force. F t Units: newton.second (N.s) The momentum p of a particle is a vector quantity equal in magnitude to the product of its mass m and its velocity v. p = m v Units: (kg.m/s)

3
7. A 3 N baseball moving toward the batter with a velocity of 15 m/s is struck with a bat which causes it to move in a reversed direction with a velocity of 30 m/s. Find the impulse and the average force exerted on the ball if the bat is in contact with the ball for 0.01 s. Fg = 3 N v0 = - 15 m/s vf = 30 m/s t = 0.01 s

4
**FΔt = mΔv =m(vf - v0) =0.31(30-(-15)) = 13.95 Ns = 1395 N m = 0.31 kg**

v0 = - 15 m/s vf = 30 m/s t = 0.01 s FΔt = mΔv =m(vf - v0) =0.31(30-(-15)) = Ns = 1395 N

7
**CONSERVATION OF LINEAR MOMENTUM**

According to the law of conservation of linear momentum, when the vector sum of the external forces that act on a system of bodies equals zero, the total linear momentum of the system remains constant no matter what momentum changes occur within the system. Although interactions within the system may change the distribution of the total momentum among the various bodies in the system, the total momentum does not change. Such interactions can give rise to two general classes of events:

8
**a. explosions, in which an original single body flies apart into separate bodies**

9
b. collisions, in which two or more bodies collide and either stick together or move apart, in each case with a redistribution of the original linear momentum.

10
**For two objects interacting with one another, the conservation of momentum can be expressed as:**

v1 and v2 are initial velocities, and are final velocities

11
**ELASTIC AND INELASTIC COLLISIONS**

If the Kinetic energy remains constant in a collision, the collision is said to be completely elastic. If the colliding bodies stick together and move off as a unit afterward, the collision is said to be completely inelastic. In inelastic collisions only the momentum is conserved.

12
In elastic collisions no permanent deformation occurs; objects elastically rebound from each other. In head-on elastic collisions between equal masses,velocities are exchanged.

13
**Inelastic collisions are characterized by objects sticking together and permanent deformation.**

14
8. A 12-g bullet is fired into a 2-kg block of wood suspended from a cord. The impact of the bullet causes the block to swing 10-cm above its original level. Find the velocity of the bullet as it strikes the block. m1 = g m2= 2 kg h = 0.1 m KE0 = PEf m1v1= ( m1+m2 )v'

15
**KE0 = PEf = 1.4 m/s m1v1= ( m1+m2 )v' = 234.7 m/s m1 = 0.012 g**

m2= 2 kg h = 0.1 m KE0 = PEf = 1.4 m/s m1v1= ( m1+m2 )v' = m/s

Similar presentations

OK

The force on an object may not be constant, but may vary over time. The force can be averaged over the time of application to find the impulse.

The force on an object may not be constant, but may vary over time. The force can be averaged over the time of application to find the impulse.

© 2018 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on metro rail in hyderabad india Marketing mix ppt on nokia phone Ppt on standing order 2-99 Ppt on power sharing in india download Ppt on solar energy system Ppt on council of ministers of india Ppt on lifelines of national economy for class 10 Ppt on uniform circular motion for class 9 Ppt on vegetarian and non vegetarian buffet Ppt on bluetooth technology downloads