1. Two different forces, acting on the same object, are measured. One force is 2.0031 N and the other force, in the same direction, is 3.12 N. These are the only forces acting on the object. Find the total force on the object using the correct number of significant figures.
2. A car slows down with constant acceleration from a speed of 111.6 km/h to 43.20 km/h over a distance of 380.0 m. How long does it take?
3. A large ice block of mass M = 80 kg is held stationary on a frictionless ramp. The ramp is at an angle 0f θ = 36.87o above horizontal. If the ice block is held in place by a tangential force along the surface of the ramp (at the angle θ above horizontal), the magnitude of force is:
N (F = mg sinθ)
4. A large ice block of mass M = 80 kg is held stationary on a frictionless ramp. The ramp is at an angle 0f θ = 36.87o above horizontal. If the ice block is held in place by a horizontal force, directed horizontally toward the center of the ice block, the magnitude of force is:
N (F = mg sinθ/cos θ)
5. A large ice block of mass M = 80 kg is held stationary on a rough ramp. The ramp is at an angle 0f θ = 36.87o above horizontal, and has a coefficient of kinetic friction between the block and the ramp μ = 0.1 . If the ice block is held in place by a tangential force along the surface of the ramp (at the angle θ above horizontal), the magnitude of force is:
N (F = mg sin θ -μ mg cos θ)
6. The displacement from the equilibrium caused by a wave on a string is given by: y(x, t) = (-0.00200 m) sin [40 m-1)x - (800 s-1)t]. What are the number of waves in 1 m .
7. What is the frequency of the above wave:
8. What is the speed of the above wave:
9. In your High School State Championship football game the intensity level of the shout of a single person in the stand at the center of the field is about 50 dB. What would be the intensity level if all 10,000 family and friends of your school shout roughly from the same distance?
10. A standing wave in a column of air with one end open and another one closed has a frequency of 390 Hz. The next higher harmonic has a frequency of 650 Hz. Determine the fundamental frequency.
11. How long is the column of air of pervious problem? Speed of sound = 340 m/s
12. An iron man is lifted by a lift that has a magnetic hook. Which one of the following free body diagrams best represents forces on the iron man? T is the tension of the cable and W is the weight of iron man, M is the magnetic force and N is the normal force.
13. A heavy box is resting on the floor and you would like to push the box to tip it over on its side, using the minimum force possible. Which of the force vectors in the diagram shows the correct location and direction of the force? The forces have equal horizontal components. Assume that there is enough friction so the box does not slide; instead it rotates around point P.
14. A dumbbell, as shown, has a connecting bar of negligible mass. If m1 = 5.0 kg and m2 = 10 kg, and are separated by 0.70 m, find the location of center of mass of the dumbbell from m1 (the left mass), from m2 (the right mass), and from the middle point between tow masses (0.35 m from each mass).
15. An equation v = (F/c)½ indicates relation between a resistance force and velocity. F has dimension ML/T2 , and v has a dimension L/T. The dimension of c is:
16. A picture hangs on the wall suspended by two strings, as shown. The tension in left string is 1.7 N. The tension in right string is:
17. A 95 N force exerted at the end of a 64 cm long wrench produces a torque of 15 N.m. What is the angle (assume to be less than 90o) between the wrench handle and the direction of the applied force?
18. A sign is supported at its top right corner, point P, as shown. The sign is square with 40 cm on each side and has 8.0 kg mass. What is the magnitude of the horizontal force that P experiences?
19. A wall-mounted lamp of mass m is suspended from a light curved rod. The bottom of the rod is bolted to the wall. The rod is also connected to the wall by a horizontal wire a vertical distance h above the bottom of the rod. What is the tension force on the horizontal wire?
Assume:
h = 12.0 cm
l = 15.0 cm
m = 2.00 kg
20. A small branch is wedged under a rock and rest on a smaller object. The smaller object is 1.0 m from the large rock and the branch is 4.0 m long. If the mass of the branch is 20.0 kg, what force must be exerted by the branch on the smaller rock?
22. You hear a sound with level 80.0 dB and you are located 10.0 m from the sound source. What is the power being emitted by the sound source?
23. There is a 1.2 m distance between a crest and an adjacent trough in a series of waves on the surface of a lake. In 30 s, 35 crest pass a buoy anchored in the lake. What is the speed of these waves?
24. A clarinet has a fundamental frequency of 147 Hz, and, when played, has one end closed.
a. How many harmonics appear below 1350 Hz?
b. If an open end tube has the same fundamental frequency, how many harmonics appear below 1350 Hz?
25. What is the effective length of a clarinet which has a fundamental frequency of 147 Hz. (closed-open tube)