7.2 Work Done by a Constant Force 7.1 Work done by a constant force The work, W, done on a system by an agent exerting a constant force on the system is the product of the magnitude F of the force, the magnitude  r of the displacement of the point of application of the force, and cos  where  is the angle between the force and the displacement vectors: W = F  r cos 

7.3 The Scalar Product of Two Vectors 7.2 Scalar product of any two vectors and

7.4 Work Done by a Varying Force Spring force F s = - kx

7.5 Kinetic Energy and the Work–Kinetic Energy Theorem K = ½ mv 2

7.6 Potential Energy of a System U g = mgy W net =  U g W app = ½ kx f 2 – ½ kx i 2

7.7 Conservative and Nonconservative Forces W C = U i - U f -  U

7.8 Relationship Between Conservative Forces and Potential Energy dU = ¯ F x dx 7.28