under the influence of its drive force, snowmobile is moving at constant velocity along a horizontal patch of snow. When drive force is shut off, snowmobile coasts to a halt.
a) During the coasting phase, what is the net external force acting on the snowmobile
b) How does work W done by the net external force depend on the magnitude anddirection of the net force and on displacement of the snowmobile?
c) What is the net force acting on snowmobile during constant-velocity phase?
a) During the coasting phase, when the drive force is shut off, the net external force acting on the snowmobile is zero. This is because there are no external forces acting on the snowmobile to accelerate or decelerate it. The only force acting on the snowmobile in this case is the force of friction, but since the snowmobile is moving at a constant velocity, the force of friction is equal in magnitude and opposite in direction to the force that was previously provided by the drive force.
b) The work done by the net external force on the snowmobile during the coasting phase is also zero. This is because work is defined as the product of the force applied on an object and the displacement of the object in the direction of the force. In this case, with no external force acting on the snowmobile, the displacement of the snowmobile is irrelevant, as there is no force acting on it to do work.
c) During the constant-velocity phase when the drive force is active, the net force acting on the snowmobile is equal in magnitude and opposite in direction to the force provided by the drive force. This is necessary to maintain a constant velocity, as per Newton's first law of motion. If the net force acting on the snowmobile were not equal to the drive force, the snowmobile would either accelerate or decelerate.