Question

If the coefficient of static friction between shoes of a runner and the track is $0.85,$ the greatest acceleration that can be generated by the runner is (here g gravitational acceleration)

• A. 1.85 g
• B. g
• C. 0.85 g
• D. 0.15 g

Answer 1

Answer: (C)

0.85 g

Answer 2

Given, $\mu_{ s }$ (coefficient of static friction) $=0.85$
As the runner is running, then force exerted by runner = frictional force (static friction) which is present between shoes and track. If $m$ is the mass of the runner, then
$f =\text { frictional force }=\mu_{ s } mg$
Then,
$ma =\mu_{ s } mg$
$a =0.85\, g$