Q8: Prb 4 - Calculate the final velocity in the horizontal direction of the rugby player, in meters per second.

Question

A 107.5 kg rugby player is initially running at 6.5 m/s in the positive direction, but collides head-on with a padded goalpost and experiences a backward force of 1.73*10⁴ N for 5.55*10^-2 s.

Answer 1

The collision will cause the rugby player to accelerate in the negative direction. Acceleration can be calculated by dividing the force by the mass of the rugby player.

a = (-1.73 × 10⁴ N)÷(107.5 kg)×(1 kg·m·s^-2÷1 N) = -161 m·s^-2

We can solve for the final velocity using the equation v = v_i + at

v_i = 6.5 m·s^-1

a = -161 m·s^-2

t = 5.55 × 10^-2 s

v = (6.5 m·s^-1) + (-161 m·s^-2)(5.55 × 10^-2s) = - 2.44 m·s^-1

That is, the velocity is 2.44 meters per second in the negative direction.