Answer:
External force on him will be 112 N
Step-by-step explanation:
We have given the mass of the sprinter m =70 kg
Acceleration of the sprinter
![a=1.6m/sec^2](https://img.qammunity.org/2020/formulas/physics/college/j91q8exr13y25bz6r4duqsrnrdzd97exv3.png)
We have to find the net external force
According to second law of motion force = mass ×acceleration
Force is dependent on the mass and acceleration
So
![F=70* 1.6=112 N](https://img.qammunity.org/2020/formulas/physics/college/8vyhk6s4y6v1w9q0px9cjudnfx6mp8p83t.png)
So external force will be 112 N