Momentum and Collisions - Mission MC3 Detailed Help


On two occasions during a football game, a defensive player collides with and stops a running back and a fullback. The fullback has more mass than the running back but they were both moving at the same speed prior to collision with the defensive player. During these two different collisions, the defensive player exerts the same force on each player for a prolonged time until the player is stopped. Compared to the fullback, the less massive running back will experience ____ momentum change, ____ impulse, and ____ collision time.


 
The momentum change of an object can be calculated from knowledge of the object's mass (m) and velocity change (v) using the formula:

Momentum Change = m • ∆v


 
Momentum Change - Impulse Theorem:
When a force is exerted upon an object in a collision, the object is said to have encountered an impulse. The impulse is simply the mathematical product of the force exerted on the object and the amount of time over which it was exerted. The impulse changes the object's momentum and is equal to the amount of momentum change.
 
Impulse = Momentum Change
or

F•t = m•∆v


 
The essential difference between the fullback and the running back is their mass. Each player has the same velocity change and encounters the same force during the collision. The fact that the two players have different mass means that the more massive player (the fullback) encounters the greatest momentum change (see Formula Frenzy section). Since momentum change is equal to impulse (see Know the Law section), then the fullback must also encounter the greater impulse. This greater impulse is due to the fact that the same collision force must endure for a longer period of time.