Finding the height above a window after an object passes it

[needhelp10]

Homework Statement

A roof tile falls from rest from the top of a building. An observer inside the building notices that it takes .20s for the tile to pass her window, whose height is 1.6m. How far above the top of the window is the roof?

Homework Equations

just having trouble determining how to solve.

The Attempt at a Solution

 

[Norfonz]

Are you familiar with Newton's equations of motion?

 

[hav0c]

try v²-u²=2as
v=u+at
s=ut+1/2at²

where u=v₀

2 will be used find out which

 

[CWatters]

Remember you can't just use 1.6/0.2 to calculate the velocity. One of the equations hav0c provided can be used to calculate the velocity at the top of the window. Another to work out the distance from roof to top of window.

 

[Nickie]

To solve this problem, we can use the equation d = vt + 1/2at^2, where d is the distance, v is the initial velocity, t is the time, and a is the acceleration. In this case, the initial velocity is 0 since the tile is falling from rest. We can also assume that the acceleration due to gravity is -9.8 m/s^2.

First, we need to find the time it takes for the tile to fall from the top of the building to the top of the window. We can use the equation v = at to find the velocity at the top of the window. Since we know the time (0.20s) and the acceleration (-9.8 m/s^2), we can solve for the velocity:

v = (-9.8 m/s^2)(0.20 s) = -1.96 m/s

Next, we can use this velocity to find the distance from the top of the building to the top of the window. We can use the equation d = vt, where v is the velocity we just calculated and t is the time it takes for the tile to pass the window (0.20s).

d = (-1.96 m/s)(0.20 s) = -0.392 m

Since we are only interested in the distance above the window, we can take the absolute value of this distance to get the final answer:

|d| = |-0.392 m| = 0.392 m

Therefore, the roof is 0.392 m above the top of the window.