Softball How much work has to be performed on a 6.5-oz

Chapter 6, Problem 28E

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Softball How much work has to be performed on a 6.5-oz softball to pitch it 132 ft/sec (90 mph)?23 Kinetic energy If a variable force of magnitude F(x) moves a body of mass m along the x-axis from x1 to x2 the body’s velocity v can be written as dx/dt (where t represents time). Use Newton’s second law of motion F=m(dv/dt)and the Chain Rule to show that the net work done by the force in moving the body from x1 to x2 is Where v1 and v2 are the body’s velocities at x1 and x2 In physics, the expression is called the kinetic energy of a body of mass m moving with velocity . Therefore, the work done by the force equals the change in the body’s kinetic energy, and we can find the work by calculating this change.