Question

As a science project, you drop a watermelon off the top of the Empire State Building, 320 m above the sidewalk. It so happens that Superman flies by at the instant you release the watermelon. Superman is headed straight down with a speed of 30.0 m/s . Part A How fast is the watermelon going when it passes Superman?

Answer 1

Answer:

24.21 m/s

Explanation:

Let the time taken by the water melon to fall is t meanwhile in the same time the distance traveled by the superman and watermelon is same.

Let the distance traveled by the super man and the water melon is same which is h.

For water melon:

Use second equation of motion

$s = ut +0.5at^2$

Here, u = 0, g = - 9.8 m/s^2, time = t

h = 0 - 0.5 x 9.8 x t^2

h =  -4.9 t^2     .... (1)

For superman:

Distance = speed x time

h = -30 x t   .... (2)

By comparing equation (1) and (2), we get

-4.9 t^2 = - 30 t

t = 2.47 second

The speed of teh watermelon is given by first equation of motion

v = u + at

here, u = 0, a = 9.8 m/s^2, t = 2.47 second

So, v = 0 - 9.8 x 2.47

v = - 24.21 m/s

The negative sign shows that the direction of velocity is downwards.