A particle starts from rest and moves with a constant acceleration of 0.5m/s2. Calculate the time taken by the particle to cover a distance of 25m.

Physics Jamb, Waec, Neco Past Questions & Answers on Speed, Velocity and Acceleration

QUESTIONS 9. A particle starts from rest and moves with a constant acceleration of 0.5m/s2. Calculate the time taken by the particle to cover a distance of 25m.

WAEC 1993 Ans: lO sec

Solutions

Initial velocity u= 0m/s

Acceleration a = 0.5m/s²

Time taken t = ?

Distance s = 25m

Velocity v = ?

To find velocity v we apply third equation of motion 

v² = u² + 2as

v² = 0² + 2(0.5)(25)

v² = 25

v = √25

v = 5m/s

Hence applying first or second equation of motion to find t

v = u + at or s = ut + ½at²

5 = 0 + (0.5)t

5 = 0.5t

t = 5/0.5

t = 10s Answer 

Or

S = ut + ½at²

25 = 0 x t + ½ (0.5) x t²

25 = 0 + ½ x 0.5 x t²

25 = 0.5 x t²/2

Cross multiplying

25 x 2 = 0.5t²

50 = 0.5t²

t² = 50/0.5

t = √ 50/0.5

t = 10s answer