Answer:
Part a)
H = 26.8 m
Part b)
error = 7.18 %
Explanation:
Part a)
As the stone is dropped from height H then time taken by it to hit the floor is given as

now the sound will come back to the observer in the time

so we will have


so we have

solve above equation for H

Part b)
If sound reflection part is ignored then in that case



so here percentage error in height calculation is given as


Answer: 
The linear momentum
is given by the following equation:
(1)
Where
is the mass and
the velocity.
On the other hand, the kinetic energy
is given by:
(2)
Which is the same as:

Now, if we double the kinetic energy, equation (2) changes to:
(3)
So, if we want to obtain the kinetic energy as shown in (3), the only option that works is increasing momentum by a factor of
or
:
Applying this in (2):


>>>As we can see, this equation is the same as equation (3)
Therefore, the correct answer is B
Answer:
Change in Displacement
Explanation:
delta/triangle = change
x = displacement
formula (if needed): final x - initial x
Newtons Law works with friction, gravity, and falls.
Also, the formula would be: F = ma
Force = acceleration * mass
Example: The force on a bike is 30 Newtons. The mass of the bike is 6 kg. What is the acceleration of the bike?