A student walks downstairs to class. Which statement correctly describes the types of energy the student has at the top of the s
1 answer:
Answer:
D potential energy at the top of the stairs, kinetic energy as she walks down
Explanation:
The potential energy of a body is the energy due to the position of the body.
At the top of the stair case, the student is at a significant height.
Kinetic energy is the energy due to the motion of the body.
As the student descends, the potential energy is changed to kinetic energy.
To find the potential energy;
P.E = mgH
m is the mass
g is the acceleration due to gravity
H is the height of the body
To find the kinetic energy;
K.E = m v²
m is the mass
v is the velocity
You might be interested in
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: