Equipment Needed:

• Statics Board
• Pulley (2)
• Mass and Hanger Set
• Inclined Plane and Cart
• Mounted Spring Scale

Experiment

• Add a 100g mass to the cart and measure and record the total mass of the cart .Calculate and record the weight of the cart-plus-mass.
• Total mass of cart= 113.7g = 0.114kg
• Weight of cart= 1.12N

• Set up the Inclined Plane on the Statics Board. Start with the plane at 15°. Put the cart on the Inclined Plane and use thread connected under a pulley to the Spring Scale to hold the cart in place on the ramp.

• Adjust the angle of inclination of the Inclined Plane to each of the values shown in the table. For accurate values, adjust the pulley and Spring Scale so that the thread remains parallel to the plane. At each value, record the measure value, F||measured, of the force parallel to the plane.

• At each value, calculate the magnitude of the force parallel to the plane, F||calculated = F sin θ, and record the calculated value.

• Calculate the percent difference between the measure and calculated values of the force parallel to the plane.

Question

• How well does the calculated force based on the vector model compare to your measure force?

=> F||measured is 29% greater than F||calculated

Normal Force

The normal force is equal to the force of the cart on the Inclined Plane, perpendicular to its surface (= F cos θ).

To measure the force of the cart on the Inclined Plane, reset the Inclined Plane to 15°. Replace the Spring Scale with a mass hanger connected by a thread over the pulley to the cart. Add masses to the mass hanger until the cart and the hanging mass are in equilibrium.

Record the total mass of the mass hanger and calculate and record the weight.

• total mass of mass hanger= 0.029kg
• weight of mass hanger= 0.28N
• How does the weight of the mass hanger compare to value of F||calculated, the component of the cart’s weight that is parallel to the plane?

=> Weight of the mass hanger is 0.2N greater than F||calculated. (The percent difference is 28%.)

Next Step: Add a second pulley to the Statics Board and set up the Spring Balance above the pulley. Tie a thread to the hole at the top of the post of the cart. Arrange the pulley so the thread from the post is in line with the post, and therefore is perpendicular to the plane. Arrange the Spring Scale so that the angle of the thread from the pulley up to the scale is vertical.

• Fㅗmeasured= 1.1N

Calculate the value of the perpendicular force as predicted by the vector model, Fㅗ calculated= Fcos θ. Record the value.

• Fㅗcalculated= l.03N

Question

How well does the calculated force based on the vector model compare to your measured force?

A: The percent difference between the calculated force based on the vector model and our measured force was 1.64%, which is almost accurate.