Chapter 11, Problem 86A

To determine

The player who has greater momentum and kinetic energy before the collision.

Explanation of Solution

Given:

Mass of player who is football linebacker, $m_1=110\text{ kg}$

Mass player who is defensive end, $m_2=150\text{ kg}$

After collision they come to stop.

Formula Used:

It is given that after the collision they come to stop means their velocity will be 0.

If velocity is zero then momentum will also be zero and this is possible only when momentum of both are equal and in opposite direction.

Therefore, before collision, both masses have equal momentum but in opposite direction.

Relation between kinetic energy and mass is given by,

  $KE=\frac{P^2}{2m}$

Here, KE is kinetic energy, P is momentum and mis mass.

Calculation:

As the momentum of both the mass are same, so from above relation, kinetic energy is inversely proportional to mass.

As $m_2>m_1$

Hence, $K{E}_1>K{E}_2$

Therefore, kinetic energy of the player who is linebacker is more than the defensive end player before collision.