<h2>
Answer: 13.61 N/m</h2>
Hooke's law establishes that the elongation of a spring is directly proportional to the modulus of the force 
applied to it, <u>as long as the spring is not permanently deformed</u>:
(1)
Where:
is the elastic constant of the spring. The higher its value, the more work it will cost to stretch the spring.
is the length of the spring without applying force.
is the length of the spring with the force applied.
According to this, we have a spring where only the force due gravity is applied.
In other words, the force applied is the weigth 
of the block:
(2)
Where 
is the mass of the block and 
is the gravity acceleration.
(3)
(4)
Knowing the force applied and 
and 
, we can substitute the values in equation (1) and find :
(5)
(6)
<u>Finally:</u>
Answer:
Cement and sand will do
Explanation:
because without it you can't build
Answer:
the acceleration during the collision is: - 5 
Explanation:
Using the formula:
we get:
Answer:
The force applied on one wheel during braking = 6.8 lb
Explanation:
Area of the piston (A) = 0.4 
Force applied on the piston(F) = 6.4 lb
Pressure on the piston (P) = 
⇒ P = 
⇒ P = 16 
This is the pressure inside the cylinder.
Let force applied on the brake pad = 
Area of the brake pad (
)= 1.7
Thus the pressure on the brake pad (
) = 
When brake is applied on the vehicle the pressure on the piston is equal to pressure on the brake pad.
⇒ P =
⇒ 16 =
⇒ = 16 ×
Put the value of we get
⇒ = 16 × 1.7
⇒ = 27.2 lb
This the total force applied during braking.
The force applied on one wheel = 
= 
= 6.8 lb
⇒ The force applied on one wheel during braking.
