Question

An aeroplane has a run of 500 m to take
off from the runway. It starts from rest
and moves with constant acceleration to
cover the runway in 30 sec. What is the
velocity of the aeroplane at the take off ?
[Ans: 120 km/hr]​

Answer 1

Answer: the answer will be 120km/hr or 100/3 m/s.

Explanation: Since the aeroplane starts from rest so its initial velocity (u) will be 0.

Let the unknown acceleration will be (a) , final velocity be (v) , distance (s) = 500m and time taken (t) = 30s.

Now , since we know that s=ut+1/2at^2.---- (1)

Thus putting the knowns in the above equation 1 will give a=10/9m/s^2.

And we also know that

v=u+at-----(2)

Putting a=10/9 m/s^2 , u=0 and t=30s in equation 2 will give v=100/3 m/s or 120km/hr.