Question

A car moving at 40km/h is to be stopped by applying brakes in the next 4.0m if the car weight 2000 kg what average force must be applied on its

Answer 1

$\huge\underline\purple{\sf ♡Answer:}$

$\large{\boxed{\sf F=3.0×{10}^{4}N}}$

$\huge\underline\purple{\sf ♡Solution:}$

Given :-

Initial velocity (u) = 40km/hr

Convert it into m/s

$\large{\sf u={\frac{40000}{3600}}}$

$\large\implies{\sf u=11.11m/s}$

Final velocity (v) = 0

Distance (s) = 4m

To find :-

Breaking force (F) = ?

━━━━━━━━━━━━━━━━━━━━━━━━━━

$\large{♡ }$$\large{\boxed{\sf a={\frac{{v}^{2}-{u}{2}}{2s}}}}$

On putting value :-

$\large\implies{\sf {\frac{{0}^{2}-{11.11}^{2}}{2×4}}}$

$\large\implies{\sf {\frac{-123.43}{8}}}$

$\large{\sf a=-15.42m/s}$

Here negative sign indicates "Decelaration"

So,

Breaking force F ,

$\large{♡ }$$\large{\boxed{\sf F=ma}}$

$\large\implies{\sf 2000×15.42 }$

$\large\implies{\sf 30840 }$

$\large{\sf F=3.0×{10}^{4}N}$

$\huge\red{♡}$$\large\red{\boxed{\sf F=3.0×{10}^{4}N}}$