A72.3-kg person, running horizontally with a velocity of +2.99 m/s, jumps onto a 13.9-kg sled that is initially at rest. (a) ignoring the effects of friction during the collision, find the velocity of the sled and person as they move away. (b) the sled and person coast 30.0 m on level snow before coming to rest. what is the coefficient of kinetic friction between the sled and the snow?

(a) 2.51 m/s

(b) 0.011

Explanation:

mass of person, M = 72.3 kg

initial velocity of person, U = 2.99 m/s

mass of sled, m = 13.9 kg

initial velocity of sled, U = 0

(a) Let the velocity of person and the sled is V

By using the conservation of momentum

M x U + m x u = (M + m) x V

72.3 x 2.99 + 13.9 x 0 = (72.3 + 13.9) V

216.177 = 86.2 V

V = 2.51 m/s

(b) initial velocity , V = 2.51 m/ s

Final velocity, V' = 0

distance, s = 30 m

Let μ be the coefficient of friction.

Use third equation of motion

0 = 2.51 x 2.51 - 2 x μ x 9.8 x 30

μ = 0.011

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