Momentum and Newton’s 2 nd Law of Motion

Momentum Momentum - an object’s tendency to keep moving  Determines how difficult it is to stop the object’s motion Formula: Momentum = Mass x Velocity

Momentum Momentum = mass x velocity Momentum = 1.5-kg x 10m/s 2 Force = 15 kg-m/s 2 or 15 N A 1.5-kg ball is thrown at 10 m/s 2. What is the ball’s momentum?

Momentum Example: A 100-kg fullback runs up the middle of the football field. He collides with a 75-kg defensive back running toward him. The more massive fullback is thrown back two meters. Although he has less mass, the defensive back has more momentum because he is moving faster than the fullback.

Momentum Law of Conservation of Momentum - the total momentum of any group of objects remains the same, unless outside forces act on the objects.

Newton’s Second Law An object’s acceleration depends on its mass and on the net force acting on it. Formula: Net Force = Mass x Acceleration or F = ma

Newton’s Second Law Force = mass x acceleration Force = 1700kg x 2m/s 2 Force = 3,400 kg-m/s 2 or 3,400N How much force is needed to accelerate a 1,700 kg car 2 m/s 2 ?

Newton’s Second Law An object will have greater acceleration if a greater force is applied to it. Example: If you push a child on a swing, the swing begins to move. The harder you push, the faster the swing accelerates.

Newton’s Second Law The mass of an object also affects the acceleration of the object. In other words: If it’s big, it’s going to move slow If you push it harder it is going to go farther

Newton’s Second Law