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 0.400kg that is traveling horizontally at 11.2m/s. Olaf's mass is 68.6kg

A)If Olaf catches the ball, with what speed vf do Olaf and the ball move afterward? Note: the following answers are incorrect: -0.06, 0.06.

B) If the ball hits Olaf and bounces off his chest horizontally at 9.00m/s in the opposite direction, what is his speed vf after the collision? Note the following answers are incorrect: 8.5

*** Fot best answer/higher ratings please explain your answer/show your work, thanks.

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 0.400kg that is traveling horizontally at 11.2m/s. Olaf's mass is 68.6kg A)If Olaf catches the ball, with what speed vf do Olaf and the ball move afterward? Note: the following answers are incorrect: -0.06, 0.06. B) If the ball hits Olaf and bounces off his chest horizontally at 9.00m/s in the opposite direction, what is his speed vf after the collision? Note the following answers are incorrect: 8.5 *** Fot best answer/higher ratings please explain your answer/show your work, thanks.

Answer 1

Part A.

Since there are no external forces applied, So momentum of system (Olaf + ball) will remain conserved

So, Using momentum conservation:

Pi = Pf

m1*u1 + m2*u2 = M*V

(Assuming positive towards left and negative towards right)

m1 = mass of ball = 0.400 kg

m2 = mass of Olaf = 68.6 kg

u1 = initial speed of ball = +11.2 m/sec

u2 = initial speed of Olaf = 0 m/sec

M = m1 + m2 = 68.6 + 0.400 = 69.0 kg

So,

V = final speed of system = ?

V = (0.400*11.2 + 68.6*0)/69.0

V = 0.0649 m/sec

See that since all the given values are in 3 significant figures, So final answer should also be in 3 significant figures

Part B.

Now when ball bounces off his chest in opposite direction, then

Using momentum conservation:

Pi = Pf

m1*u1 + m2*u2 = m1*v1 + m2*v2

v1 = final speed of ball = -9.00 m/sec (-ve sign since in opposite direction)

v2 = final speed of Olaf = ?

So,

0.400*11.2 + 68.6*0 = 0.400*(-9.00) + 68.6*v2

v2 = 0.400*(11.2 + 9.00)/68.6

v2 = 0.118 m/sec = final speed of Olaf

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