Olaf is standing on a sheet of ice that covers the football stadium parking lot

Question

Olaf is standing on a sheet of ice that covers the football stadium parking lot in Buffalo, New York; there is negligible friction between his feet and the ice. A friend throws Olaf a ball of mass 0.400 kg that is traveling horizontally at 10.5 m/s . Olaf's mass is 73.9 kg .(Figure 1)

A- f Olaf catches the ball, with what speed vf do Olaf and the ball move afterward?

B- What fraction of the initial kinetic energy was lost in this perfectly inelastic collision?

C- If the ball hits Olaf and bounces off his chest horizontally at 8.40 m/s in the opposite direction (ouch!), what is his speed vf after the collision?

Olaf is standing on a sheet of ice that covers the football stadium parking lot in Buffalo, New York; there is negligible friction between his feet and the ice. A friend throws Olaf a ball of mass 0.400 kg that is traveling horizontally at 10.5 m/s . Olaf's mass is 73.9 kg .(Figure 1) A- f Olaf catches the ball, with what speed vf do Olaf and the ball move afterward? B- What fraction of the initial kinetic energy was lost in this perfectly inelastic collision? C- If the ball hits Olaf and bounces off his chest horizontally at 8.40 m/s in the opposite direction (ouch!), what is his speed vf after the collision? D- What fraction of the initial kinetic energy was lost in this inelastic collision?

Explanation / Answer

A) Momentum Conservation

m1u1 + m2u2 = (m1 + m2) v

0.4*10.5 + 0 = (0.4 + 73.9) v

v = 0.4*10.5 / (0.4+73.9) = 0.0565 m/s

speed vf = 0.0565 m/s

B) Kinetic energy lost = 0.5*m1*u1^2 - 0.5*(m1+m2)*v^2

= 0.5*0.4*10.5^2 - 0.5*(0.4+73.9)*(0.0565)^2 = 21.93 J

Fraction of KE lost = 21.93 / (0.5*0.4*10.5^2) = 0.995

C) m1 u1 + m2 u2 = m 1v1 + m2 v2

0.4*10.5 + 0 = - 0.4*8.4 + 73.9*v2

v2 = (0.4*10.5 + 0.4*8.4)/73.9 = 0.1023 m/s

speed vf after the collision = 0.1023 m/s

D) Fraction of kinetic energy lost = ( 0.5*m1*u1^2 - (0.5*m1*v1^2 + 0.5*m2*v2^2) / (0.5*m1*u1^2)

= (0.5*0.4*10.5^2 - (0.5*0.4*8.4^2 + 0.5*73.9*0.1023^2)) /(0.5*0.4*10.5^2)

= 0.342

-------------------------------------------------------------------------------------------------------------------

Answers

A) speed , vf = 0.0565 m/s

B)  Fraction of KE lost = 0.995

C) speed vf after the collision = 0.1023 m/s

D) Fraction of kinetic energy lost = 0.342

Related Questions

Navigate

• Browse (All)
• Browse O
• Subjects

---

---

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