Impulse Lab

In this lab, we used two metal rings attached to 2 carts with a force probe to explore the relationship between time, force, and impulse in a collision.

Impulse is defined as a change in momentum. But how doe we measure change? Let's say that you go to the Giants World Series game with $100 dollars in your pocket. During the game, you buy a coke, cotton candy, popcorn, and a sweatshirt. The total cost of the novelties is $50. Since you spent $50, the change would be recorded as -$50. It is expressed in the following equation:

Change (delta) = end - start

Impulse = the momentum after a collision - the momentum before the collision (addressed as a negative because momentum is a vector)

The relationship between force, time, and impulse is also expressed in an equation:

J (impulse) = F (force) x t (time) or J= deltaP = P(after)- P(before)

According to Newton's Third Law, for every force, there is an equal and opposite force.

in a collision, the impulse is always the same because time and force are inversely proportional, meaning that if the force increases, the time during the collision decreases and vice versa.

For example, a boy is jumping off of a table. When his feet collide with the ground, his knees instinctively bend. By bending his knees, the boy allows the collision to last longer, making the force of the collision smaller on his body. If the boy had collided with the floor with his knees locked, the collision would have happened faster (less time) and the force on the boy's legs would be greater. The bones would not be able to absorb the amount of force and unfortunately, his bones would break but no matter how the boy lands, the impulse of the collision would remain the same.

Real World Connection:

There is a reason why airbags are installed in every modern car. Collisions involving automobiles are particularly lethal to humans. In accidents, the airbag increases the amount of time that a human body comes in contact with the steering wheel, making the force of the collision smaller on the human body and saving millions of lives.