Question

Cite your answers in m/s and to three significant figures. Question 1 3 pts Aman holding a rock sits on a sled that is sliding across a frozen lake (negligible friction with a speed of 0.490 m/s. The total mass of the sled, man, and rock is 97.5 kg. The mass of the rock is 0.320 kg and the man can throw it with a speed of 17.0 m/s. Both speeds are relative to the ground. Determine the speed of the sled in m/s if the man throws the rock forward (i.e. in the direction the sled is moving). Question 2 3 pts What is the speed of the sled in the previous question if the rock is thrown in the opposite direction?

Answer 1

here,

1)

mass of sled , men and rock , M = 97.5 kg

mass of rock , m = 0.32 kg

initial speed of men , u = 0.49 m/s

final speed of rock , v2 = 17 m/s

let the final speed of man be v1

using conservation of momentum

M * u = (M - m) * v1 + m * v2

97.5 * 0.49 = (97.5 - 0.32) * v1 + 0.32 * 17

solving for v1

v1 = 0.44 m/s

the final speed of sled is 0.44 m/s in forward direction

2)

mass of sled , men and rock , M = 97.5 kg

mass of rock , m = 0.32 kg

initial speed of men , u = 0.49 m/s

when the rock is thrown in opposite direction

final speed of rock , v2 = - 17 m/s

let the final speed of man be v1

using conservation of momentum

M * u = (M - m) * v1 + m * v2

97.5 * 0.49 = (97.5 - 0.32) * v1 - 0.32 * 17

solving for v1

v1 = 0.55 m/s

the final speed of sled is 0.55 m/s in forward direction