Question

In the absence of air resistance, all objects fall at the same rate according to

                                   y = vi t +1 / 2 g t2

where vi is the initial velocity of the falling object. If dropped from rest, the equation becomes

y = 1 / 2 g t2

For a 2 m release point, calculate the impact velocity  

1. if dropped from rest

2. If released with a downward velocity of 2.00 m/s.

       C. if released with an upward velocity of 2.00 m/s.

Answer 1

Part A.

Let the impact velocity is v

In Uniform accelerated motion

v²=v_i²+2gd

In this case v_i=0 and d=2m

so v²=0+2(9.8)2

v=6.26 m/s

Part B.

if v_i=2m/s

then

v²=2²+2(9.8)2

v=6.57 m/s

Part c.

if v_i=2 m/s in upward direction then at the releasing point it is 2m/s in downward diection

so this case is same as case2

v=6.57m/s