Question

Suppose that a force of 20.40N acts through and parallel to a displacement of 135.2m on some object with mass 5.800kg. problem. There are no other forces to be considered in this How much work would the force have done? Give your answer in Joules with four significant figures but do not type the units If the only effect was to increase its speed from an initial value of zero, how fast would it now be going? Give your answer in m's with three significant figures.I Now suppose that the object did not start at rest. Does the amount of work done depend upon the initial velocity? Does the final velocity depend upon the magnitude of the initial velocity? Does the change in velocity depend upon the magnitude of the initial velocity? Does the change in kinetic energy depend upon the magnitude of the initial velocity?

Answer 1

Given data The force is F = 20.40 N The displacement is s = 135.2 m The mass is m = 5.8 kg The work done is W =F middot s = (20.40)(135.20) = 2758.08 J The acceleration is a = F/m = 20.40/5.8 = 3.52 m/s^2 The final speed is v^2 - u^2 = 2as v^2 - 0 = 2as v = squareroot 2as = squareroot 2(3.52)(135.2) = 38.85 m/s No work done depends on force and displacement Yes final velocity depends on initial velocity Yes change in velocity depends on magnitude of initial velocity Yes