Running at 2.0 m/s, Bruce, the 45.0-kg quarterback, collides with Biff, the

90.0-kg tackle, who is traveling at 7.0 m/s in the other direction. Upon

collision, Biff continues to travel forward at 1.0 m/s. How fast is Bruce

knocked backwards?

Respuesta :

Answer:

14m/s

Explanation:

Given data

M1=45kg

U1=2m/s

M2=90kg

U2=7m/s

V1=?

V2=1m/s

Applying the expression for elastic collision

M1U1+M2U2=M1V1+M2V2

Substitute

45*2+90*7=45*V1+90*1

90+630=45V1+90

720-90=45V1

630=45V1

Divide both sides by 46

V1=630/45

V1=7.5m/s

Hence Bruce's speed is 14m/s