Chapter 7, Problem 15A

Referring to Figure 7.14, how many horizontal forces are exerted on the cart? What is the horizontal net force on the cart?

To determine

Number of horizontal forces are exerted on the cart and the net force on the cart.

Explanation of Solution

Introduction:

Force appears in pair. According to Newton's third law of motion, for every action force there is equal and opposite reaction force.

Horse pulls the cart in forward direction let it is denoted by P. Horse applies the force on the cart in forward horizontal direction that is F. Due to friction between the ground and the wheel of the cart, the force of friction is in opposite direction that is f. This force pulls the horse that is p. So there are two horizontal forces acting on the cart (F and f), which are in opposite direction to each other.

As the cart moves in the forward direction, so the force exerted by the horse on the cart overcomes the frictional force.

Conclusion:

Two forces acting on the cart, horse pulls the cart in forward direction and frictional forces opposes the motion of a cart. Net force acting on the cart is not zero since horse pulls the cart forward. The net force on the cart is F-f.