If a body slides over a surface the force exerted on the body by the surface in a direction
opposite to the direction of the motion is called the kinetic frictional force. The kinetic
frictional force is proportional to the normal force (the force acting
An object, which moves under the action of a force, proportional to the objects
displacement from its equilibrium position, will undergo simple harmonic motion
(SHM). As an example consider a mass vibrating on the end of a massless spring.
As the mass is
Chapter 5
THE COEFFICIENT OF FRICTION
5.1
Introduction
If a body slides over a surface the force exerted on the body by the surface in a direction
opposite to the direction of the motion is called the kinetic frictional force. The kinetic
frictional force
7. Put the string that over the pulley and make sure that the string running from the
cart to the pulley is parallel to the track.
8. Suspend 20g from the overhanging string.
9. Put 200g on the cart itself.
10. Record the total mass of the cart (M).
11. R
Trial M(kg)
m(kg)
m
F (N)
Accel( )
net
Total Mass(kg)
m
Accel Theory(
)
% Diff
?
4.4
Questions
1. Why must friction be ignored?
2. What relationships exist between the graphed variables?
3. How does the actual acceleration compare with the theoretical acc
If an object is at rest on an inclined surface, the force of friction, which keeps it from
sliding, is the static frictional force. If the angle of the surface is gradually raised, an angle
will be found where the body just begins to slide. This angle is
Where ac is the centripetal acceleration (centripetal means toward the center), v is
the speed of the object and r is the radius of its circular path. In the alternate form, , is
the angular velocity. From Eq. 6.1, Eq. 6.2 and Newtons second law,F = ma ca
7. Find the value of the coefficient of friction from the graph made in step 6. Remember
how to find the value of proportionality constant from the graph.
8. Place the block on the plane and elevate the plane until the block will slide down at a
constant
2. Allow the bob to hang straight down. Adjust the reference pointer so that the point
of the bob is aligned with it, as shown in Figure 6.1. Measure the radius of motion at
this setting.
3. Hook the spring up to the bob. Run a string from the bob over th
Figure 4.1: Dynamics Cart Setup
A Cart, B Mass, C Smart Pulley, D Table Clamp, E Mass
4.3
Procedure
For this activity, a Smart Pulley will measure the motion of a cart using a string that is
attached to the weights suspended over the pulley. The computer
14. Click REC on the computer, then release the cart.
15. Click STOP on the computer, just before the hanging masses hit the floor. Be careful,
do not let the cart damage the smart pulley.
16. In the graph window, click the Statistics button to open the s
Lab Stand
Lab Clamp
Meter Stick
1.3
Procedure
1. Hand a spring up from a hook. Record the position of the end of the spring.
2. Add mass to the spring and record the new position of its end. Repeat this step for at
least six different readings of mass
Chapter 2
Understanding Motion
2.1
Introduction
When describing the motion of an object, knowing its location relative to a reference point,
how fast and in what direction it is moving, and how it is accelerating is essential. This
lab uses a ultrasonic r
2.3
Procedure
1. Connect the science workshop interface and make sure that it is on.
2. Connect the motion sensors stereo plugs in Digital Channels 1 and 2 with the yellow
plug begin inserted into Channel 1.
3. Open the Science workshop file named P01 MOT
14. Right-click the highlighted area. Select Fit, then Linear Fit.
15. The slope that is displayed gives the velocity of your motion. Record this value.
16. Determine how well your plot fits by finding the percent difference between your velocity and the
How close should you be to motion sensor at the beginning?
How far away should you move from the motion sensor?
How long should this motion last?
What is the percent difference between your velocity and the velocity shown on the graph?
What is the CHITEST
Chapter 3
Vector Forces and Equilibrium
3.1
Introduction
A quantity which has both magnitude and direction is called a vector.
This laboratory
conserves the addition of vectors and equilibrium of forces on objects. The technique for
adding vectors is diff
The first condition that must be met for a point body at rest to remain at rest is that
the resultant of all applied forces acting on the body equal zero. If forces applied at
the same time to a body at rest produce a non-zero resultant, the equilibrant i
4. Calculate the theoretical value for the magnitude and direction of the equilibrium of
the two forces in steps 1 and 2. How does this compare to the value found in step 3.
5. Repeat the experiment with three forces, use 100g at 45o , 140g at 115o and 70
Chapter 6
Centripetal Force and Acceleration
6.1
Introduction
According to Newtons first law of motion, an object will remain at rest or in a state of
uniform linear motion unless acted upon by an unbalanced force. If an object travels in a
circle, its st
Chapter 7
Conservation of Linear Momentum
7.1
Introduction
In this laboratory we will investigate elastic collisions by carts. Linear momentum, p, is the
product of the mass of the object, m, times its velocity v.
p = mv
(7.1)
The total momentum of a syst
8. Calculate the velocity of the projectile using the results of step 7 and equation 8.10.
9. Compare the results of step 5 and step 8 by finding the percent difference.
8.4
Questions
1. Is the collision between the projectile and the pendulum bob elastic
3. Replace the crossbar on the apparatus. Use the wing nuts to secure in place a 100gslotted mass, 15 cm from the axis of rotation on each side of the crossbar. (See Figure
9.1).
4. Call the mass on the right side of the cross bar, m1 , and that on the le
Chapter 10
Torques and Rotational Equilibrium
10.1
Introduction
The second condition for equilibrium of a rigid body states that the sum of the torques acting
on the body must be zero. That is, all of the torques, which would cause clockwise rotation,
mus
Figure 11.1: Simple Harmonic Oscillator
A Lab Stand, B Meter Stick, C Mass, D Spring
In this lab you will measure the period of vibration of a mass on a vertically-hanging
spring and compare it to this theoretical result. Since the spring you will be usin
where vh is the velocity of the falling mass as it hits the floor and is the angular velocity of
the spinning crossbar and masses. Since the gravitational force on mh is constant, the
system will be accelerated uniformly and the final velocity of mh can b
Chapter 11
Simple Harmonic Motion
11.1
Introduction
An object, which moves under the action of a force, proportional to the objects displacement
from its equilibrium position, will undergo simple harmonic motion (SHM). As an example
consider a mass vibrat
to equilibrium. (Be sure to find the weight of the second hanger before placing it on
the meter stick.)
6. Calculate the torque produced in step 5 and compare it to that from step 4.
7. Place two weight hangers on the right side of the meter stick at dist
Stop Watch
11.3
Procedure
1. Determine and record the mass of the spring.
2. Hang the spring from the support clamp. Determine the spring constant of the spring
by collecting at least six different values of the weight F added to the spring and the
sprin
(9.6) Substituting eq 9.5 into eq 9.6 and solving
for v, we get:
2h
v=
(9.7)
t
so we can find the velocity of the falling mass. Since the friction in the axle and the
pulley is small, we can assume that the mechanical energy of the system will be conserve