The kinetic energy K of an object of mass m moving at a speed v is defined as K=(1/2)mv^2. It seems reasonable to say that the speed of an object--and, therefore, its kinetic energy--can be changed by performing work on the object. In this problem, we will explore the mathematical relationship between the work done on an object and the change in the kinetic energy of that object.

Question

Let us now consider the situation quantitatively. Let the mass of the sled be m and the magnitude of the net force acting on the sled be Fnet. The sled starts from rest.

Consider an interval of time during which the sled covers a distance s and the speed of the sled increases from v_1 to v_2. We will use this information to find the relationship between the work done by the net force (otherwise known as the net work) and the change in the kinetic energy of the sled.

1.Find the net force F_net acting on the sled.?
(Express your answer in terms of some or all of the variables m, s, v_1, and v_2)
2.Find the net work W_net done on the sled.?
(Express your answer in terms of some or all of the variables Fnet and s.)

Answer 1

How thoughtful of you to copy the complete lecture leading up to the question. Now please let us see own effort in solving the problem.

Work done is F x s.

The change in kinetic energy is ____?

Answer 2

(m((v^2)^2-(v^1)^2)/2s)