Answer:
h = 38.41 m
Explanation:
Given that,
A ball is thrown horizontally from the top of a building and strikes the sidewalk after 2.8 s.
We need to find the height of the building. Let it is h.
Initial speed of the ball, u = 0
Using second equation of motion to find h as follows :

So, the building is 38.41 m tall.
Answer:
3.6m
Explanation:
if you are at a building that is 46m above the ground, and the professor is 1.80m, the egg must fall:
46m - 1.80m = 44.2m
the egg must fall for 44.2m to land on the head of the professor.
Now, how many time this takes?
we have to use the following free fall equation:

where
is the height,
is the initial velocity, in this case
.
is the acceleration of gravity:
and
is time, thus:

clearing for time:

we know that the egg has to fall for 44.2m, so
, and
, so we the time is:

Finally, if the professor has a speed of
, it has to be at a distance:

and t=3.002s:

so the answer is the professor has to be 3.6m far from the building when you release the egg
It's C. increasing the masses of the objects and decreasing the distance between the objects
Answer:
Direction
Explanation: Hope this helps!
Using KE = 1/2mv^2
m = mass (80kg)
v = velocity (?)
KE = kinetic energy (2500J)
2500/((1/2) x (80)) = v^2
Square root the answer to get: 7.91 m/s