Question

If a car at rest accelerates uniformly and attains a speed of 75 km/h in 10 s then it covers a
distance of
(A) 50 m
(B) 100 m
(C) 200 m
(D) 400 m

the answer is 100 m
I need explanation​

Answer 1

Given that, a car starts from rest (means the initial velocity of the car is 0 m/s) and attains a speed of 75 km/hr in 10 sec.

Here, initial velocity of car (u) = 0 m/s, speed of car or final velocity of the car (v) is 75 km/hr and time (t) = 10 sec

We have to find the distance (s) covered by the car.

First of all convert the Final velocity of the car in m/s. To convert km/hr into m/s, multiply with 5/18.

Final velocity = 75 × 5/18 = 20.83 m/s

Using the First Equation Of Motion,

v = u + at

20.83 = 0 + a(10)

20.83 = 10a

20.83/10 = a

2.083 = a

Therefore, the acceleration of the car is 2 m/s².

Now,

Using the Second Equation Of Motion,

s = ut + 1/2 at²

s = 0(10) + 1/2 × 2 × (10)²

s = 0 + 1/2 × 2 × 100

s = 100

Therefore, the distance covered by the car is 100 m.

Option B) 100 m