Answer:
Explanation:
For this exercise let's use hooke's law
F = - k x
where x is the displacement from the equilibrium position.
x = 
if we have several springs in series, the total displacement is the sum of the displacement for each spring, F the external force applied to the springs
x_ {total} = ∑ x_i
we substitute
x_ {total} = ∑ -F / ki
F / k_ {eq} = -F 
1 / k_ {eq} = ∑ 1 / k_i
if all the springs are the same
k_i = k
The law applied here is Newton's first law, also known as, law of inertia.
This law states that: A body will retain its state of rest or motion unless acted upon by an external force.
If you are moving and the bus suddenly stops, your body will lurch forward trying to retain its state of motion until it comes to rest and changes its state by the external force acted on it.
If you are at rest and the bus suddenly moves, your body will lurch backwards trying to retain its state of rest and opposing the force of motion until it is forced to change its state by this force.
Inertia is the property of all matter by which it tends to remain
in constant, uniform motion unless acted on by external force.
Answer:
4
Explanation:
As you can see in the free body diagram there are 4 forces acting on the body.
Because for example a lightning bolt is an electromagnetic wave. Lighting bolts can hurt you or even kill you. But others waves cant harm you.
Hope this helps
