Suppose that 5 J of work is needed to stretch a spring from its natural length of 36 cm to a length of 45 cm. Required:
a. How much work is needed to stretch the spring from 38 cm to 43 cm? (Round your answer to two decimal places.) J
b. How far beyond its natural length will a force of 45 N keep the spring stretched? (Round your answer one decimal place.

If the force applied to an object remains constant, is more power needed for the object to move faster ? explain

Aperson gives a shopping cart an initial push along a horizontal floor to get it moving, and then lets go. the cart travels forward along the floor, gradually slowing as it moves. consider the horizontal force(s) on the cart while it is moving forward and slowing. which of the following statements is correct? (a) both a forward and a backward force are acting on the cart, but the forward force is larger. (b) only a forward force is acting which diminishes with time. (c) both a forward and a backward force are acting on the cart, but the backward force is larger. (d) only a backward force is acting, no forward force.

Explain why electric current cannot exist if a current doesn't have a voltage source.