Ahot-air balloon is descending at a rate of 1.9 m/s when a passenger drops a camera. if the camera is 47 m above the ground when it is dropped, how much time does it take for the camera to reach the ground? if the camera is 47 m above the ground when it is dropped, what is its velocity just before it lands? let upward be the positive direction for this problem.

The camera lands in t=2.91s with a velocity:

Explanation:

The initial velocity of the camera is the same as the hot-air ballon:

Kinematics equation:

when the camera lands, y=0:

We solve this equation to find t:

t1=-3.29s       This solution have not sense in our physical point of view

t2=2.91s    

So, the camera lands in t=2.91s

We replace this value in v(t):

waves moving from a fast medium to a slow medium will experience a reflection as light travels more slowly than red light. total internal reflection occurs when the critical angle is.

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