Question

Using the work energy theorem. What is the velocity of a 850kg car after starting at rest when 13,000J of work is done to it.

Answer 1

When the car starts moving it acquires kinetic energy.

For this problem the formula of kinetic energy is:

`(1)/(2)mv^2`

Where m is the mass of the car = 850kg, and v is the speed of the car.

If we consider insignificant the energy lost by friction with soil and air we can propose the following equation:

Applied energy = Kinetic energy acquired by the car.

`13000\ J = (1)/(2)mv^2\\\\13000\ J = (1)/(2)(850)v^2\\\\(13000(2))/(850) = v^2\\\\v = \sqrt{(13000(2))/(850)}\\\\v = 5.531 m/s`

The velocity is 5.531 m/s