Question

A horse continues to apply a force in order to move a cart with a constant speed. Explain.

Answer 1

Force is applied by the horse in order to overcome the losses due to friction. Continuous force is necessary to keep moving the cart with constant velocity.

Complete answer:
When the cart is moving several forces act on the cart like gravitational force, frictional force. These forces oppose the motion of the cart and produce resistance against the motion. To overcome frictional force the horse has to keep applying the force to move the cart.

Additional Information:
The motion of a body depends on many factors like velocity, acceleration, friction etc. When motion starts then the initial force required is used to overcome the static friction. After motion starts the kinetic friction comes into the picture and stays during the whole motion. Now a motion can start when initial static friction is overcome after that motion can be continued when the kinetic friction is overcome. The analysis of force is necessary to calculate the time taken in the journey and the power and energy required in the journey. Motion analysis can be done by using the equations of motion moreover the force analysis can be done by using Newton’s second law or applying the force equilibrium on the body.

Note:
Extra energy is always needed to overcome the losses that occur due to friction. Continuous motion can only occur by the body when sufficient energy is provided to the body that overcomes all the losses.