Answer:
External force on him will be 112 N
Explanation:
We have given the mass of the sprinter m =70 kg
Acceleration of the sprinter 
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 
So external force will be 112 N
Static electricity can be an alternating current.
Answer:
power output/transformer efficiency multiply by 100%
Explanation:
derrive the formula from efficiency=power output/power input multiply by 100%