Question

a body starts from rest and moves with uniform acceleration of 5 for 8s. from that time the accelration ceases . find the distance covered in 12s starting from rest

Answer 1

Dear Student,

There seems to be some error in the equation. The car first accelerates with 5 ms^-2 then it accelerates with constant velocity. It should have been, then it continues with constant velocity.

So, the car moves from rest with acceleration 5 ms^-2 for 8 s.

Distance travelled in this time is, S₁ = ut + ½ at²

=> S₁ = 0 + ½ × 5 × 8²

=> S₁ = 160 m

The velocity it attains in this 8 s is,

v = u + at

=> v = 0 + 5 × 8 = 40 m/s

So, distance travelled with this velocity for another 4 s (12-8 = 4) is, S₂ = 40 × 4 = 160 m

So, the total distance travelled by the car is = S₁ + S₂ = 160 + 160 = 320 m