ANSWER
The required force is
[tex]350N[/tex]
EXPLANATION
The force needed to accelerate a 70kg runner at [tex]5ms^{-2}[/tex] is the product of the mass of the runner in kilograms and the acceleration in meters per seconds square.
The equation is given by,
[tex]F=ma[/tex]
where
[tex] m = 70kg[/tex]
and
[tex]a=5m{s}^{-2}[/tex]
This implies that,
[tex]F=70\times 5N[/tex]
We multiply to get,
[tex]F=350N[/tex]
Therefore the needed force is 350 Newtons.
