You are trying to find out how high you have to pitch a water balloon in order for it to burst
when it hits the ground. You discover that
the balloon bursts when you have pitched it
to a height of 11 m.
With what velocity did the balloon hit
the ground? The acceleration of gravity is
9.8 m/s
2
. The positive direction is up, so the
velocity when it hits is negative.
Answer in units of m/s.

-14.68 m/s

Explanation:

You are given the height of the balloon that it is "dropped": 11 m. Since the final velocity of a projectile is 0 m/s at the top of its flight, we can say that the initial velocity is 0 m/s and the displacement is -11 m (the balloon "starts" at the top of its trajectory).

We know the acceleration of the balloon is -9.8 m/s².

Use this kinematic equation that relates all four variables (displacement, initial velocity, final velocity, acceleration):

Substitute known variables into the equation.

Since the positive direction is up, the velocity when it hits the ground must be negative. The balloon hits the ground with a velocity of -14.68 m/s.

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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