What is the difference in energy between the n x = n y = n z = 4 state and the state with the next higher energy? What is the percentage change in the energy between the n x = n y = n z = 4 state and the state with the next higher energy? (b) Compare these with the difference in energy and the percentage change in the energy between the n x = n y = n z = 400 state and the state with the next higher energy.
What is the difference in energy between the n x = n y = n z = 4 state and the state with the next higher energy? What is the percentage change in the energy between the n x = n y = n z = 4 state and the state with the next higher energy? (b) Compare these with the difference in energy and the percentage change in the energy between the n x = n y = n z = 400 state and the state with the next higher energy.
What is the difference in energy between the
n
x
=
n
y
=
n
z
=
4
state and the state with the next higher energy? What is the percentage change in the energy between the
n
x
=
n
y
=
n
z
=
4
state and the state with the next higher energy? (b) Compare these with the difference in energy and the percentage change in the energy between the
n
x
=
n
y
=
n
z
=
400
state and the state with the next higher energy.
The velocity of an elevator is given by the graph shown.
Assume the positive direction is upward.
Velocity (m/s)
3.0
2.5
2.0
1.5
1.0
0.5
0
0
5.0
10
15
20
25
Time (s)
(a) Briefly describe the motion of the elevator.
Justify your description with reference to the
graph.
(b) Assume the elevator starts from an initial position
of y = 0 at t=0. Deriving any numerical values
you
need from the graph:
i. Write an equation for the position as a
function of time for the elevator from
t=0 to t = 3.0 seconds.
ii. Write an equation for the position as a
function of time for the elevator from t = 3.0
seconds to t = 19 seconds.
(c) A student of weight mg gets on the elevator
and rides the elevator during the time interval
shown in the graph. Consider the force of con-
tact, F, between the floor and the student. How
Justify your answer with reference to the graph
does F compare to mg at the following times?
and your equations above.
i. = 1.0 s
ii. = 10.0 s
Students are asked to use circular motion to measure the
coefficient of static friction between two materials. They
have a round turntable with a surface made from one of
the materials, for which they can vary the speed of rotation.
They also have a small block of mass m made from the sec-
ond material. A rough sketch of the apparatus is shown in
the figure below. Additionally they have equipment normally
found in a physics classroom.
Axis
m
(a) Briefly describe a procedure that would allow you
to use this apparatus to calculate the coefficient of
static friction, u.
(b) Based on your procedure, determine how to
analyze the data collected to calculate the
coefficient of friction.
(c) One group of students collects the following
data.
r (m)
fm (rev/s)
0.050
1.30
0.10
0.88
0.15
0.74
0.20
0.61
0.25
0.58
i. Use the empty spaces in the table as needed to
calculate quantities that would allow you to
use the slope of a line graph to calculate the
coefficient of friction, providing labels with…