Download Physics Force Lab

Name(s):
Block:
Physics Force Lab
Part 1: Calculate your weight: Mass and weight - w = m g
Materials – weighing scale gives your mass in lb
Mass (kg) = mass (lb) / 2.2
Weight in Newtons converted to mass in kg
Weight on Earth _________ g = 9.80 m/sec2
Mass on Earth
_________ m = w / g
Weight on Moon _________ gmoon = 1.65 m/sec2
Mass on Moon
_________
Weight on Jupiter _________ gJupiter = 29.6 m/sec2
Mass on Jupiter _________
Draw a free body diagram that shows each of the forces acting on you, the force
plate and the floor.
Conclusions:
Why does your mass stay the same regardless of what planet you measured?
What is the sum of all the forces in your free body diagram?
ΣF = _____
How does your weight change as you go up or down on an elevator?
Part 2: Coefficient of Friction
Put ONLY the block on an incline and keep increasing the angle of the incline till
the block just begins to slide. Measure the angle of the incline ‘’. See if the angle
changes. Do three trials and take the average value for the coefficient. Use the
equation μs = tan 




Average value of s



Coefficient of static and kinetic friction using a force sensor and labquest:
1. Attach the dual force sensor to the Channel 1 of Labquest2. The dual force
sensor can be in the 10 N or 50 N range.
2. The sensor should be calibrated at 0 N and 9.8 N in the manner shown by
teacher
3. Make the wooden track horizontal, place the block of wood on it with the
weight
4. Hook the sensor and gently start to pull on it. Start the run button and
record data in the graph mode. When the block just begins to move,
continue pulling it at a constant velocity.
5. Select the portion of the graph of F vs t, where you were pulling at a
constant velocity (i.e. constant force)
6. Go to Analyze and chose statistics (force). Read the mean value of Force at
the right for the selected area. That is the force of kinetic friction.
7. At the beginning of the plot data, you would have a spiked value where the
block was just beginning to move.
8. Select that portion, and go to Analyze and choose statistics. This maximum
value of Force would give you the force of static friction
9. Repeat the exact same steps 3 to 6, just flipping the surface of the block
μs = fs / FN
Mass (kg)
Static
Kinetic
larger
surface
Kinetic smaller
surface
1
2
3
1
2
3
1
μk = fk / FN
Normal
Force (N)
Pull (N)
friction
Coefficient
+
+
+
+
+
+
+
Conclusions:
Can the coefficient of friction ever be zero? Explain.
Can the coefficient of friction ever be greater than one? What would that mean?
Give three ways that you could decrease the coefficient of friction.