Question

Under the influence of its drive force, a snowmobile is moving at a constant velocity along a horizontal patch of snow. When the drive force is shut off, the snowmobile coasts to a halt. The snowmobile and its rider have a mass of 130 kg. Under the influence of a drive force of 217 N, it is moving at a constant velocity whose magnitude is 6.36 m/s. The drive force is then shut off. Find (a) the distance in which the snowmobile coasts to a halt and (b) the time required to do so.

(a)	s =		_______ ---Select--- m ,W, N ,m/s^2, J ,s ,m/s
(b)	t =		________ ---Select--- m/s, s, m, W ,m/s^2, N ,J

Answer 1

(a) When moving with constant velocity, the drive force 217 equals the frictional force.

Frictional force = - 217N. Minus to indicate this is opposite to the applied force.

Acceleration due to friction = force / mass = - 217/130 = -1.669m/s^2

When the drive force is shut off, the velocity is 6.36m/s.

Acceleration = - 1.669m/s^2

Final velocity = 0

Using v^2 -u^2 = 2ad and noting v = 0,

d =- u^2/2a = - (6.36)^2 / [2*(-1.669) = 12.12 m

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(b)

time = v-u /a = 0-6.36 / -1.669 = 3.81 s