Question

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

Answer 1

5.53 m/s

Step-by-step explanation:

The work is equal to the change in the kinetic energy, so

`\begin{gathered} W=\Delta KE \\ W=(1)/(2)m(v^2_f-v^2_i)^{}^{} \end{gathered}`

Since the car starts at rest, the initial velocity vi = 0 m/s, so we can solve for the final velocity vf as follows

`\begin{gathered} W=(1)/(2)mv^2_f \\ 2W=mv^2_f \\ (2W)/(m)=v^2_f \\ v_f=\sqrt[]{(2W)/(m)} \end{gathered}`

So, replacing the work W = 13,000J and the mass m = 850kg, we get:

Therefore, the velocity is 5.53 m/s