Answer:
Explanation:
Given
height from which ball is dropped
and it rises to a height of
A person caught the ball in mid-way i.e. at a height of from pavement
time taken to reach the bottom is given by
where y=displacement
u=initial velocity
a=acceleration
t=time
here initial velocity is zero i.e.
Similarly to reach of height time taken is
The ball is caught in mid-way i.e. ball travel a distance of
time taken is
total time taken
total time =3.429 s
Answer:
Em₀ = U = m g h , Em_{f} = K = ½ m v²
Explanation:
When a car is on a ramp it has a certain amount of mechanical energy. At the highest point of the ramp the mechanical energy is fully potential given by
Em₀ = U = m g h
As part of this energy descends down the ramp, part of this energy is transformed into kinetic energy and has one part of each, even though the sum remains the initial energy
Em = K + U = ½ m v² + mg y
y <h
when it reaches the bottom of the ramp it has no height therefore there is no potential energy, all of it has been transformed into kinetic energy
Em_{f} = K = ½ m v²
This energy transformation is in the case that the friction force is zero.
If there is a friction force, it performs work against the low car, it is reflected in an increase in the internal energy (temperature) of the car. In this case the energy in the lower part is less than the initial one by a factor
= - fr L
therefore the numeraire values of the velocity are lower, due to the energy lost by friction.