Section 3: MomentumBy: Najmunnahar K. 8G

Motion & Momentum

• The mass of an object is the amount of matter in an object.

• Inertia is the tendency of an object to resist a change in motion. Inertia increases as the mass of an object increases.

• It is easier to stop a child from running than to stop an adult from running because a child has less mass.

Mass & Inertia

Momentum• The momentum of an

object in motion is related to how hard it is to stop the object, and can be calculated from the following equation:

p= mv• Because velocity has a

direction , momentum also has a direction.

• The law of conservation of momentum states that in a collision, the total momentum of the object that collide is the same before and after the collision.

• This is true for the collision of billiard balls, atoms, cars, football players, or any other matter.

Law of Conservation of Momentum

• Objects that collide will bounce off each other, like when a bowling ball hits the pins, some of its momentum is transferred to the pins. The ball slows down, and the pins speed up.

• In other collisions, objects will stick to each other after the collision, like the two football players. When one player tackles the other, they both change speeds, but momentum is conserved.

Using Momentum Conservations

In this picture when the first ball hits the second ball, it transfers its momentum to the second ball make the second ball move faster than the first ball.

If two objects of the same mass moving at the same speed collide head on, they will rebound and move with the same speed in the opposite direction. The total momentum is zero before and after the collision.

Understanding the Conservation of Momentum

Colliding & Bouncing Off• In some collisions, the objects

involved bounce off each other.

• The law of conservation of momentum can be used to determine how these object moved after they collide.

• When two identical objects moving with the same speed collide head on and bounce off, before the collision the momentum of each object is the same, but in opposite directions.

• The total momentum is zero.