Question

Velocity of body changes from 18 km/hr to 90
km/hr in 10 sec. Calculate acceleration in
body.

Answer 1

Answer:

9m/s

Explanation:

the formula of acceleration is change in velocity /time (v-v/t) so 18-90/10 cancel the zero in 10 and 90 then it becomes 18-9/1 then 18-9 is equal to 9.

the si unit of acceleration is meters per second m/s.

Thank you.

Answer 2

Answer:

The acceleration of the body is equal to 2ms⁻².

Explanation:

Given: If the velocity of body changes from 18 km/hr to 90km/hr in 10 sec. Then,

Initial velocity of the body , $u=18Kmhr^{-1}$

Final velocity of the body, $v=90km/hr$

Convert km/hr into m/s:

1km=1000m and 1hr = 3600s

Therefore, $u=\frac{18*10^{3}m}{3600s}=5ms^{-1}$

And, $u=\frac{90*10^{3}m}{3600s}=25ms^{-1}$

The time taken, $t=10sec$

From the first equation of motion;

  $v-u =at$

⇒ $a=\frac{v-u}{t}$

⇒  $a=\frac{25-5}{10}$

∴   $a=2ms^{-2}$

Therefore acceleration is equal to 2ms⁻².