 Solution

ID: past-exam-of-the-physics-1-paper-of-the-university-of-oxford/2015/3/a/solution

Snow leaves perpendicular to the motion in the rider's frame, so its outgoing horizontal velocity in the ice frame is

v

. During

d t

, incoming snow brings zero horizontal momentum and outgoing snow carries

σ v d t

. Thus

M \overset{v}{˙} = - σ v, v_{A} (t) = v_{0} e^{- σ t / M} .

Although the sled does not retain snow, it must continually supply the snow's departing horizontal momentum.

 New to topics? Read the docs here!