Question

A balloon starts rising from the ground with an acceleration of 1.25 ms⁻². After 8 s, a stone is released from the balloon. The stone will (Taking g = 10 m s⁻²)(a) begin to move down after being released(b) reach the ground in 4 s(c) cover a distance of 40 m in reaching the ground(d) will have a displacement of 50 m.

Answer 1

Answer:

B) 4s

Explanation:

Initial velocity of balloon = u = 0

Acceleration = a = 1.25 ms⁻²

Time = t = 8 sec

Distance travelled in 8 seconds -

S = ut+1/2at²

s = 1/2×1.25×(8)²

s = 40

Now balloon will drop down with initial velocity u =v =10m/s with acceleration a = -g = -10m/s^2 and cover distance = -40m

Thus,

S = ut+1/2at²

-40 = 10t -1/2(10) t²

= t²-2t-8 = 0

On solving the quadratic t = -2 and 4

Since the time can not be negative therefore = 4

Thus, the stone will 4s to reach the ground.