Equations: Heat: Q = mcδt Hooke s Law: F = kx Resultant: R 2 = Rx 2 + Ry 2 Tan θ= Ry/Rx

Transcription

1 Final Phys pts 9 November 2011 Name Equations: Heat: Q = mcδt Hooke s Law: F = kx Resultant: R 2 = Rx 2 + Ry 2 Tan θ= Ry/Rx Practical Questions 1) (5 pts) Measure the length of the provided cylinder with the vernier caliper. Length = cm 2) (10 pts) Determine the mass of the aluminum cylinder with the provided materials. Assume all the clips have equal mass. Draw a figure and/or show any data or calculations for full credit. Mass of cylinder = g 3) (10 pts) Place 150 g on the spring, including the hanger. Set the spring in motion. Measure the period of the mass on the spring. Show any data or calculations for full credit.

2 Multiple Choice Circle the Correct Answer (2 points each) 4) Which of these forces provides the centripetal force for a ball being twirled in a circle? a. the gravitational force c. the torque b. the tension force d. the normal force 5) You want to see-saw with your (much larger) Cousin Jimbo. You sit on the seat of the seesaw. Where should Cousin Jimbo sit to make this easier? a. on the same side as you c. at the pivot point b. on the other seat d. closer to the pivot point 6) A spring is described by a spring constant of 10 N/m. It is compressed from equilibrium by 0.5 m. What is the magnitude of the force required to compress the spring? a. 0.2 N c. 5 N b. 50 N d. 20 N 7) A material has a density of 1200 kg/m 3. It has a volume of 0.2 m 3. What is its mass? a. 240 kg c. 6,000 kg b. 44 kg d kg 8) A material with a higher specific heat (compared to one of lower specific heat) a. has a bigger mass c. is more dense b. requires more energy to raise its d. requires less energy to raise its temperature for the same mass temperature for the same mass

3 Short Answer 9) (10 pts) Using trigonometry (component method) or a graphical method, calculate the sum of these two vectors. Show your work. A = 10 N at 90 B = 15 N at 40 10) (5 pts) As we set up in lab, a cart of mass, m, is on an inclined plane of angle, θ. The cart is attached to a sting, pulley and weight that apply a force, F, up the plane. Draw a force diagram or figure showing all the forces on the cart if it is traveling DOWN the plane at a constant velocity. Label all forces.

4 11) (10 pts) You combine 50 g of copper shot initially at 100 C with 100 g of water at 20 C. The final equilibrium temperature is 30 C. The specific heat of water is 1 cal/(g C). What is the specific heat, c, of copper? Show your calculations. 12) (5 pts) What are the period and radius of motion for this object traveling in a circular path? The displacement versus time is graphed in this figure: Simple Harmonic Motion (x vs. t) Displacement (meters) time (seconds)

5 13) (10 pts) Determine the spring constant, k, from the graph. The equation of the line is: T 2 = (4π 2 /k) (m l + m h +fm s), where m l is the mass of the load, m h is the mass of the hanger, and m s is the mass of the spring. 1.2 Period Squared, T 2 (s 2 ) Mass, m l + m h (kg) 14) (20 pts) The following data were taken for the surface area of a sphere, which is represented by this equation: A = 4πr 2 Plot the data (so that it is linear) on the graph paper and interpret it appropriately to determine the value for π. The actual value for π is Compute the percent difference between your experimental value (from the graph) and the actual value. Show your calculations for full credit. Area (m 2 ) radius (m)