Question

A soccer player starts from rest and accelerates forward, reaching a velocity of 8.00m/s in 2.50s. a) What was his average acceleration? b) what average force did he exert backward on the ground to achieve this acceleration? The players mass is 70.0kg, and air resistance is negligible

Answer 1

a)

$$a_{avg}=\frac{\Delta v}{\Delta t}=\frac{8}{2.5}=3.20\frac{m}{s^2}$$

b)

$$F=ma_{avg}=(70)(3.2)=224\ N$$