Physics 201 MWF10:20 Fall 2003 (Ford)

Final Exam Chapts. 1--17 in Cutnell and Johnson 6th ed

Show all your work. Partial credit will be given if earned. Write your answers in the blanks provided.


(12 pts) 1. A small rock of mass 0.020 kg is released from rest at point A, at the rim of a hemispherical bowl. The radius of the bowl is 0.80 m. When the rock reaches point B its speed is 3.0 m/s.



a) How much work is done by the friction force on the rock during its motion from point A to point B?

Ans. __________________

b) At point B, what is the normal force exerted by the bowl on the rock?

Ans. _________________


(12 pts) 2. A rock is projected from the roof of a building. The rock has an initial velocity of 10 m/s at an angle of 53° above the horizontal. The rock strikes the ground a horizontal distance of 18 m from the base of the building.



a) How much time elapses from when the rock is projected until it strikes the ground?

Ans. __________________

b) How much time elapses from when the rock is projected until it reaches its maximum height above the ground?

Ans. __________________

c) What is the speed of the rock just before it strikes the ground?

Ans. _________________

d) What is the speed of the rock when it is at its maximum height above the ground?

Ans. ______________


(12 pts) 3. A uniform board 6.0 m long that has mass m is attached to a wall by a frictionless hinge. The board is held in a horizontal position by a cable that runs from one end of the board to the wall. The cable makes an angle of 37° with the board. The tension in the cable is 250 N.



a) For an axis at the hinge, what is the magnitude of the torque on the board exerted by the cable?

Ans. ____________________

b) What is the mass m of the board?

Ans. ____________________

c) What are the magnitude and direction of the resultant force exerted by the hinge on the board?

Ans. __________________


(12 pts) 4. A 80-kg box is pulled up a ramp by means of a rope that is parallel to the surface of the ramp. The ramp is inclined at 37° above the horizontal. The coefficient of kinetic friction between the box and the ramp is 0.50 and the box accelerates up the ramp with an acceleration of 2.0 m/s².



a) While the box is moving, what is the friction force exerted on the box by the surface of the ramp?

Ans. _______________________

b) What is the tension T in the rope?

Ans. ______________________


(10 pts) 5. A 50.0-kg skater is traveling due east at a speed of v₁. A 70.0-kg skater is moving due south at a speed v₂. They collide and hold onto each other after the collision. After the collision they move together with a speed of 6.0 m/s in a direction of 36° east of south. What are the speeds v₁ and v₂ of each skater before the collision? Assume that the ice is perfectly smooth and that friction between the ice and the skaters can be neglected.

Ans. v₁ = ________________

v₂ = _____________________


(9 pts) 6. A small block with mass 0.50 kg is attached to a horizontal spring that has a spring constant of 600 N/m. The block is moving in simple harmonic motion on a horizontal frictionless surface. The amplitude of the motion is 0.20 m.

a) What is the speed of the block when it is displaced 0.10 m to the left of its equilibrium position?

Ans. _________________

b) What is the maximum kinetic energy of the block during its motion?

Ans. __________________

c) What is the magnitude of the maximum force exerted by the spring on the block during its motion?

Ans. ___________________


(10 pts) 7. The temperature of 5.0 moles of a monatomic ideal gas is decreased from 600 K to 400 K. The gas constant is R = 8.31 J/mol·K. Calculate the work done by the gas and the change in the internal energy of the gas if the process is carried out at constant pressure and if it is carried out at constant volume. In each case you must specify if each quantity is positive or negative. A gas does positive work when its volume increases.

a) constant pressure

Ans. W = ___________________

U = _____________________

b) constant volume

Ans. W = ___________________

U = _____________________


(6 pts) 8. A uniform cylinder has mass 5.0 kg and radius 0.10 m. The moment of inertia for an axis through its center is mr²/2. The cylinder is rolling without slipping on a horizontal surface. The total kinetic energy of the cylinder is 36 J. What is the translational speed of the center of mass of the cylinder?

Ans. _________________


(6 pts) 9. Two loud speakers A and B are driven by the same amplifier and therefore emit sound waves in phase and with the same frequency f. Speaker B is due east of speaker A and point P is 6.0 m due east of speaker B. The smallest frequency f for which there is destructive interference at point P for the waves from A and B is 170 Hz. The speed of sound in air is 340 m/s. What is the distance between A and B?



Ans. ____________________


(6 pts) 10. A standing waves with frequency 60 Hz is produced on a string that is tied to rigid supports at each end. The distance between adjacent nodes of the standing wave is 0.15 m. What is the speed of transverse waves on the string?

Ans. ___________________


(5 pts) 11. Transverse waves on a horizontal string have an amplitude of 5.0 mm and a wavelength of 0.20 m. A point on the string travels through a distance of 0.60 m in 1.0 s as it undergoes its transverse up and down motion. What is the speed of the transverse waves on the string?

Ans. ________________