Question

A 0.010 kg arrow is fired from a bow whose string exerts a force of 110 N on the arrow over a distance of 0.80 m. What is the SPEED of the arrow as it leaves the bow?

Answer 1

The change of energy is equal to work done

$$K_f-K_i=W=Fd$$ $$\frac{mv_f^2}{2}-0=Fd$$

Hence, the final speed of the arrow

$$v_f=\sqrt{\frac{2Fd}{m}}=\sqrt{\frac{2\times 110\times 0.80}{0.010}}=133\:\rm m/s.$$