A) 
The total energy of the system is equal to the maximum elastic potential energy, that is achieved when the displacement is equal to the amplitude (x=A):
(1)
where k is the spring constant.
The total energy, which is conserved, at any other point of the motion is the sum of elastic potential energy and kinetic energy:
(2)
where x is the displacement, m the mass, and v the speed.
We want to know the displacement x at which the elastic potential energy is 1/3 of the kinetic energy:
Using (2) we can rewrite this as
And using (1), we find
Substituting 
into the last equation, we find the value of x:
B) 
In this case, the kinetic energy is 1/10 of the total energy:
Since we have
we can write
And so we find:
In an extremely simplified explanation,
What happens is that the steam (heat) that is generated by the burning of coal is used to rotate the motor of the steam engine.
Answer:
Regular exercise and physical activity increase muscle strength, bone density, flexibility, and stability. Physical fitness can reduce your risk for and resilience to accidental injuries, especially as you get older.
Answer:
-10m/s
Explanation:
only the magnitude of the velocity will change due to the change in direction of the car.
Answer:
<h2>1567.09 N/m</h2>
Explanation:
Step one:
given data
mass m=5kg
compression x= 3.13cm to m= 0.0313m
<em>According to Hooke's law, provided the elastic limit of an elastic material is not exceeded the extension e is directly proportional to the applied force</em>
F=ke
where
k= spring constant in N/m
e= extension/compression in
Step two:
assume g= 9.81m/s^2
F=mg
F=5*9.81
F=49.05N
substitute in the expression F=ke
49.05=k*0.0313
k=49.05/0.0313
k=1567.09 N/m
<u>The force constant (in N/m) of the spring is 1567.09 N/m</u>
