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Map ling learning Nate the Skate was an avid skateboarding. In particular, Nate

ID: 1460238 • Letter: M

Question

Map ling learning Nate the Skate was an avid skateboarding. In particular, Nate would often don a protective suit of Bounce-Tex, which he invented, and after working up a high speed on his skateboard, would collide with some object. In this way, he got a gut feel for the physical properties of collisions and succeeded in combining his two passions. On one occasion, the Skate, with a mass of 119 kg, including his armor, hurled himself against a 847-kg stationary stàtue of Isaac Newton in a perfectly elastic linear collision. As a result, Isaac started moving at 1.77 m/s and Nate bounced backward. What were Nate's speeds immediately before and after the colision? (Enter positive numbers.) Ignore friction with the ground student whose main non-physics interest in life was high-speed Before: Number m/s After Number m/s By the way, this brief bio of Nate the Skate is written in the past tense, because not long ago he forgot to on his Bounce-Tex before colliding with the Washington Monument in a perfectly inelastic collision. We will miss him. Hint sbout us sreers partners privacy policy terms of use contact u

Explanation / Answer


m1 = 119 kg                   m2 = 847 kg


speeds before collision


u1 = ? m/s                   u2 = 0 m/s

speeds after collision


v1 = ?                         v2 = 1.77


initial momentum before collision


Pi = m1*u1 + m2*u2

after collision final momentum

Pf = m1*v1 + m2*v2

from moentum conservation


total momentum is conserved

Pf = Pi


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

(119*u1) + (847*0) = (119*v1) + (847*1.77).....(1)

from energy conservation


total kinetic energy before collision = total kinetic energy after collision


KEi = 0.5*m1*u1^2 + 0.5*m2*u2^2


KEf =   0.5*m1*v1^2 + 0.5*m2*v2^2


KEi = KEf


0.5*m1*u1^2 + 0.5*m2*u2^2 = 0.5*m1*v1^2 + 0.5*m2*v2^2


0.5*119*u1^2 + 0.5*847*0^2 = 0.5*119*v1^2 + 0.5*847*1.77^2 ........(2)

u1 = 7.18 m/s <---------------answer

after collision


v1 = -5.414 m/s <<------answer