Question

Sprinting near the end of a race, a runner with a mass 63 kg accelerates from a speed of 25 m/s to a speed of 26 m/s in 54 s. To gain speed the runner produces a backward force on the ground, so that the ground pushes the runner forward, providing the force necessary for the acceleration. Calculate this average force. Answer in units of N.

Answer 1

Answer:

1.1655 N

Explanation:

Given that,

Initial speed, u = 25 m/s

Final speed, v = 26 m/s

Time taken, t = 54 s

So, Applying equation of motion as:

$v=u+at\\\Rightarrow a=\frac{v-u}{t}\\\Rightarrow a=\frac{26-25}{54}\ m/s^2\\\Rightarrow a=0.0185\ m/s^2$

According to the Newton's second law of motion:-

$Force=Mass\times Acceleration$

Mass = 63 kg

So,

$Force=63\times 0.0185\ kgm/s^2$

Force = 1.1655 N