Question

Question -

☞ If a car at rest accelerates uniformly to a velocity of 144km/hr in 20sec.
Find distance travelled by the car in 1st 20sec​

Answer 1

Answer :—

$\longmapsto\tt\bf$Disatnce travelled is 400m .

Given:—

$\longmapsto\tt\bf$Initial velocity( u )= 0m/s

$\longmapsto\tt\bf$Final velocity( v ) = 144km/ hour

$\longmapsto\tt\bf$Time( t ) = 20sec

To Find :—

$\longmapsto\tt\bf$ Distance travelled by car in 1st 20 sec=?

Solution :—

v= 144km/ hr

➟ v = $144 \times \dfrac{1000}{3600} m/sec$

➟ v= 40m/s

We know, from 1st equation of motion that:

$\longmapsto\tt\bf$v = u + at

➟ a = $\dfrac{v - u}{t} - - - - i$

We know from 2nd equation of motion that:

$s = ut + \dfrac{1}{2} a {t}^{2} - - - - ii$

Substitute the value of a from i to ii

$s = ut + \dfrac{1}{2} ( \dfrac{v - u}{t} ) {t}^{2}$

$\implies s = 0 \times t + \dfrac{1}{2} \times (40 - 0) {t}^{2}$

$\implies s = \dfrac{1}{2} \times 40 \times 20$

${\bold{\boxed{\large{\longmapsto s = 400m}}}}$

$\therefore$ Disatnce travelled is 400m .

Answer 2

Answer:

the distance traveled is 400 m