Question

the velocity of a car at 10:50 a.m. is 60 km per hour and at 10:52 a.m. it is 80km/h .assuming constant acceleration in the given period ,find its value​

Answer 1

Answer :-

Given

▪️Velocity at 10:50 am = 60 km/h

= 60 × 5/18

= 150/9 m/s

▪️Velocity at 10:52 am = 80 km/h

= 80 × 5/18

= 200/9 m/s

▪️Acceleration is constant

Now from above

▪️Time = 2 min = 120 sec

Now as we have

▪️v = u + at

$\longrightarrow \dfrac{200}{9}= \dfrac{150}{9} + 120(a)$

$\longrightarrow \dfrac{200}{9}- \dfrac{150}{9} = 120(a)$

$\longrightarrow \dfrac{200 - 150}{9}= 120(a)$

$\longrightarrow \dfrac{50}{9}= 120(a)$

$\longrightarrow a = \dfrac{\dfrac{50}{9}}{120}$

$\longrightarrow a = \dfrac{50}{9\times120}$

$\longrightarrow a = \dfrac{5}{9\times12}$

$\longrightarrow a = \dfrac{5}{108}$

Answer 2

v = 80km/h

u = 60 km/h

v- u = 20 km/h

= 20*5/18 m/s

= 100÷18 m/s

t = 2 minutes = 2*60 s = 120 sec

according to first law of motion

v = u + at

a = (v-u)/ t

a=100÷18÷120 m/s^2

= 0.0462 m/s^×