Question

During a football game, a receiver has just caught a pass and is standing still. Before he can move, a tackler, running at a velocity of +3.0 m/s, grabs and holds onto him so that they move off together with a velocity of +1.8 m/s. If the mass of the tackler is 100 kg,determine the mass of the receiver in kilograms. Assume momentum is conserved.

kg

Answer 1

m1 ( mass of receiver) = ?

m2 ( mass of tackler ) = 100 kg

v1 = speed of reciver = 0

v2 = speed of tackler = 3 m/s

initial momentum before collision Pi = m1*v1 + m2*v2

after collision

speed of receiver + tackler = v = 1.8 m/s

final momentum after collision Pf = (m1+m2)*v

momentum is conserved

n change in momentum

dP = 0

Pf - Pi = 0

Pf =Pi

(m1+100)*1.8 = (m1*0) + (100*3)

(m1 + 100 )*1.8 = 300

m1 + 100 = 300/1.8

m1 + 100 = 167

m1 = 167 - 100

m1 = 67 kg <<----------ANSWER