Two hockey players, Robert (mass 60.0kg ) and Mike (mass 45.0kg ), are practicin

Question

Two hockey players, Robert (mass 60.0kg ) and Mike (mass 45.0kg ), are practicing. Robert stops to tie his skates and, while at rest, is struck by Mike, who is moving at 13.0m/s before he collides with him. After the collision, Mike has a velocity of magnitude 8.00m/s at an angle of 55.1? from his initial direction. Both players move on the frictionless, horizontal surface of the rink.

1. What is the magnitude of Robert's velocity after the collision?

2. What is the direction of Robert's velocity after the collision?

3. What is the change in total kinetic energy of the two players as a result of the collision?

Please show work also so I understand ! :)

Explanation / Answer

along x axis ( initial)

Mr*Urx + Mm*Umx = Mr*Vrx + Mm*Vrx

0 + (45*13) = (60*Vrx) + (45*8*cos55.1)

Vrx = 6.32 m/s

alon y axis ( perpendicualr to initial

Mr*Ury + Mm*Umy = Mr*Vry + Mm*Vry

0 + (45*0) = (60*Vry) + (45*8*sin55.1)

Vry = -4.92 m/s

1) Vr = sqrt(Vrx^2 +Vry^2) = 8.0m/s

2) direction = tan^-1(Vry/Vrx) = 37.9

3)K1 = 0.5*45*13*13 = 3802.5 J

K2 = (0.5*60*8*8) +(0.5*45*8*8) = 3360 J

dK = K2 - k1 = -442.5 J

K2 < K1

the collision is inelastic

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.