Question

A car start from rest and acquire a velocity of 54 km/h in 2 sec. Find
(i) the acceleration
(ii) distance travelled by car assume motion of car is uniform?

Answer 1

HI there !!!

Here ,
As the car is starting from rest ,
Initial velocity = u = 0 m/s

Final velocity = v = 54 km/hr
To convert km/hr to m/s , we multiply it by 5/18

Final velocity = v = 54 km/hr = 54 x 5/18
= 15 m/s

Time = t = 2 sec

a = acceleration

Equation of motion :
v = u + at

15 = 0 + 2a

a = 15/2 = 7.5 m/s²

s = distance traveled

Equation of motion :

s = ut + 1/2 at²


= 0 + 1/2 × 7.5 × 2²
= 15 metres

Answer 2

Given,

Initial velocity u = 0

Final velocity v = 54 km/hr

= 15 m/s

Time t = 2 sec

Calculation:-

i) The acceleration:-

Acceleration = Change in velocity / Time

a = (v - u)/t

= (15 - 0)/2

= 7.5 m/s² Ans.

ii) Distance travelled by car assume motion of car is uniform:-

s = ut + 1/2 at²

= 0 * 2 + 1/2 * 7.5 * (2)²

= 15 m Ans.