A balloon starts rising from rest from the ground with an acceleration of 1.25 m/s2. After 8s, a stone is released from the balloon.
The stone will.
(a)cover a distance of 40m
(b)have a displacement of 50 m
(c)each the ground in 4s
(d)begin to move down after being released

Question

A balloon starts rising from rest from the ground with an acceleration of 1.25 m/s2. After 8s, a stone is released from the balloon. 
The stone will.
(a)cover a distance of 40m
(b)have a displacement of 50 m 
(c)each the ground in 4s
(d)begin to move down after being released

anonymous · Answer

My first question is won't there be two accelerations acting on the baloon

parthkohli · Answer

Oh... yeah, but you will ignore the acceleration due to gravity.

parthkohli · Answer

1.25 m/s2 here is the overall adjusted acceleration.

parthkohli · Answer

After 8 seconds, the balloon AND the stone will have a velocity of 10 m/s in the upwards direction. Do you agree?

parthkohli · Answer

So when the stone is released, it will move in the upward direction for one second before it starts to move down.

anonymous · Answer

yes by v=u+at

parthkohli · Answer

The initial height of the balloon:$$h_i = \dfrac{1}{2} \times 1.25 \times 8^2 = 40 m$$

anonymous · Answer

So b is correct

anonymous · Answer

why it will move upward

parthkohli · Answer

Because of inertia. When you are moving upwards and release a stone, then that stone will also initially move upwards.

parthkohli · Answer

The distance it moves further upwards after being released can also be figured out by using the formula $H_{max} = u^2/2g$. Here, $u = 10$ so $H_{max} = 5$.

anonymous · Answer

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this path right?

parthkohli · Answer

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