Rolling friction .<span> the force that slows down the movement of a rolling object</span>
sliding friction.
Sliding friction : The opposing force that comes into play when
one body is actually sliding over the surface of the other body
is called sliding friction. e.g. A flat block is moving over a
horizontal table.
Kinetic or dynamic friction: If the applied force is increased further
and sets the body in motion, the friction opposing the motion is called
kinetic friction
AuthenticD3mon and I talked it over and agreed that
natural gas is the least polluting fossil fuel.
(See comments under his answer.)
Our values can be defined like this,



The problem can be solved for part A, through the Work Theorem that says the following,

Where
KE = Kinetic energy,
Given things like that and replacing we have that the work is given by
W = Fd
and kinetic energy by

So,

Clearing F,

Replacing the values


B) The work done by the wall is zero since there was no displacement of the wall, that is d = 0.
So, the time needed before you hear the splash is approximately <u>2.06 s</u>.
<h3>Introduction</h3>
Hi ! In this question, I will help you. This question uses two principles, namely the time for an object to fall freely and the time for sound to propagate through air. When moving in free fall, the time required can be calculated by the following equation:



With the following condition :
- t = interval of the time (s)
- h = height or any other displacement at vertical line (m)
- g = acceleration of the gravity (m/s²)
Meanwhile, for sound propagation (without sound reflection), time propagates is the same as the quotient of distance by time. Or it can be formulated by :

With the following condition :
- t = interval of the time (s)
- s = shift or displacement (m)
- v = velocity (m/s)
<h3>Problem Solving</h3>
We know that :
- h = height or any other displacement at vertical line = 19.6 m
- g = acceleration of the gravity = 9.8 m/s²
- v = velocity = 343 m/s
What was asked :
= ... s
Step by step :
- Find the time when the object falls freely until it hits the water. Save value as





- Find the time when the sound propagate through air. Save value as




- Find the total time




<h3>Conclusion</h3>
So, the time needed before you hear the splash is approximately 2.06 s.