A car starting from rest accelerates uniformly to acquire a speed 20 km h-1 in 30 min. The distance travelled by car in this time interval will be – (i) 600 km (ii) 5 km (iii) 6 km (iv) 10 km

5 km

Reason – As we know,

v = u + at

Given,

u = 0

v = 20 km h-1

t = 30 min = 1/2​ h

Substituting the values in the formula above, we get,

20 = 0 + a × 1/2

or, a = 40 km h^-2

Now, S = ut +  1/2 at²

Substituting the values in the formula above we get,

S = 0 × 0.5 + 1/2 × 40 × (1/2)²

= 0 + 1/2 × 40 × 1/4

= 5 km