Question

A car starts from rest to cover a distance x. The coefficient of friction between the road and tyres is µ. The minimum time in which the car can cover distance x is proportional to –

• A. µ
• B. $\frac { 1 } { \sqrt { \mu } }$
• C. $\sqrt { \mu }$
• D. $\frac { 1 } { \mu }$

Answer 1

Answer: (B)

$\frac { 1 } { \sqrt { \mu } }$

Answer 2

V = u + at

v² = u² + 2as

0 = u + (– µg)t

0 = u² + 2(– µg) s

t = $\frac { \mathrm { u } } { \mu \mathrm { g } }$

u = $\sqrt { 2 \mu \mathrm { gs } }$

t = $\frac { \sqrt { 2 \mu \mathrm { gg } } } { \mu \mathrm { g } }$ ̃ t µ $\frac { 1 } { \sqrt { \mu } }$