Forces Momentum What Is an Objects Momentum All

Forces Momentum

What Is an Object’s Momentum? All moving objects have what Newton called a “quantity of motion. ” Today it’s called momentum. Momentum is a characteristic of a moving object that is related to the mass and the velocity of the object.

The momentum of a moving object can be determined by multiplying the object’s mass by its velocity. Momentum = Mass x velocity

Since mass is measured in kilograms and velocity is measured in meters per second, the unit for momentum is kilograms times meters per second. Like velocity, acceleration, and force, momentum is described by both a direction and a strength. The momentum of an object is in the same direction as its velocity.

The more momentum a moving object has, the harder it is to stop. Which is easier to stop, a baseball or a car moving at the same speed?

The velocity of an object also affects the amount of momentum it has. For example, a tennis ball served by a professional tennis player has a large momentum. Although the ball has a small mass, it travels at a high velocity.

Conservation of Momentum Imagine you’re driving a go-cart. If you ran into another go-cart that was at rest and got stuck to it, what do you think would happen to your momentum?

Before you hit the other go-cart, your momentum was just your mass times your velocity. How has the additional mass changed that momentum?

It actually hasn’t changed it at all!

A quantity that is conserved is the same after an event as it was before. The law of conservation of momentum states that, in the absence of outside forces like friction, the total momentum of objects that interact does not change.

The amount of momentum two cars have is the same before and after they interact. The total momentum of any group of objects remains the same, or is conserved, unless outside forces act on the objects.

“Non-Sticky” Collisions When two objects of the same mass don’t stick together and outside forces (such as friction) are negligible, the objects just trade velocities. The car that is going faster before the collision will end up slowing down, and the car that is going slower before the collision will end up speeding up.

“Sticky” Collisions Sometimes objects end up sticking together during a collision. Look at the example on page 55 in your book. These two cars, which have the same mass, got tangled together after they collided.

Since the green car was at rest and had a momentum of zero, only the blue car had any momentum before the collision. After they collided and stuck together, the cars shared that momentum. The total momentum of the two cars stayed the same.

Colliding Cars Lab Homework is pages 56 & 57