The term mutual velocity, can be described as?

[JohnnyB212]

The term "mutual" velocity, can be described as?

Homework Statement

A 110 kg tackler moving at 3.0 m/s meets head-on (and tackles) a 95 kg halfback moving at 7.5 m/s. What will be their mutual velocity in meters/second immediately after the collision?

Homework Equations

m1 = 110kg
V01 = 3.0 m/s
m2 = 95 kg
V02 = 7.5 m/s
V1f = Final Velocity of the 110 kg tackler
V2f = Final Velocity of halfback

V1f = ((m1-m2)/(m1+m2))V01

V2f = ((2m1)/(m1+m2))V01

The Attempt at a Solution

V1f = 1.68
V2f = 24.68Am I correct for both? How would I determine the mutual velocity? I noticed V02 wasnt used, so I'm a little confused, any help would be appreciated, thanks.

 

[Doc Al]

"Mutual" in the sense of "shared in common". The two players stick together after the collision and thus have the same velocity.

Redo your calculations with that in mind.

 

[JohnnyB212]

"Mutual" in the sense of "shared in common". The two players stick together after the collision and thus have the same velocity.

Redo your calculations with that in mind.

Was the equation correct?

 

[JohnnyB212]

Oh! I caught myself on the V1f, which is actually .5897

Still, confused about the mutual portion. How are you to determine the common similarities of two completely different numbers?

 

[Doc Al]

Was the equation correct?

No.

Oh! I caught myself on the V1f, which is actually .5897

Still, confused about the mutual portion. How are you to determine the common similarities of two completely different numbers?

Instead of plugging into some formula (which doesn't apply to this situation), why not just apply conservation of momentum?

The collision is perfectly inelastic (they collide and move together). Hint: Direction matters--they are headed toward each other.