Question

A 110 kg football player runs at 8 m/s and plows into an 80 kg referee that is standing still on the football field. The referee moves forward at 5 m/s.

a. What is the momentum of the football player before the collision?

b. What is the momentum of the referee before the collision?

c. What is the total momentum before the collision? (Hint: add a and b)

d. What is the momentum of the referee after the collision?

e. What must be the momentum of the football player after the collision?

f. Find the football players speed after the collision.

Answer 1

See below

Step-by-step explanation:

(a) Momentum can be solved with the formula: p = mv, where m and v are mass and velocity, respectively. So, p = (110kg) * (8m/s) = 880 kg* m/s

(b) Since v = 0 m/s, p = 0 kg * m/s

(c) The total momentum is 880 + 0 = 880 kg * m/s

(d) pi = pf

880 = 190 *vf -----> vf = 4.631 m/s

p = mv = (80kg) * (4.631 m/s) = 370.53 kg * m/s

(e) p = mv = (110kg) * (4.631 m/s) = 509.47 kg * m/a

(e) 4.631 m/s (as solved in part (d) )