Answer:
Thread.
Explanation:
The most common form consists of a cylindrical shaft with helical grooves or ridges called threads around the outside.
C) CFCs is the correct answer.
Answer:
Explanation:
Given
car A had a head start of 
and it starts at x=0 and t=0
Car B has to travel a distance of 
where
is the distance travel by car A in time t
distance travel by car A is

For car B with speed 



Answer:
C Restoring Force
Explanation:
Given data
Fs=-kx
According to Hokes Law, provided the elasticity of an elastic material is not exceeded the extension xis directly proportion to the applied force F
From the expression, F represent the Restoring Force in Newton
Answer:

Explanation:
Since work done is in the form of potential energy, we will use the formula of potential energy here.
We know that,
<h3>P.E. = mgh </h3>
Where,
m = mass = 20 kg
g = acceleration due to gravity = 10 m/s²
h = vertical height = 20 m
So,
<h3>Work done = mgh</h3>
Work done = (20)(10)(20)
Work done = 4000 joules
Work done = 4 kJ
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