Physics Problem Set
- One end of a nylon rope is tied to a stationary support at the top of a vertical mine shaft 80 cm. deep. The rope is stretched taut by a box of mineral samples with mass 20.0 kg at the lower end. The mass of the rope is 2.0 kg. The geologist at the bottom of the mine signals to his colleague at the top by jerking the rope. If the wave frequency 2 Hz, what are the other characteristics of the wave? (WAVES)
- A police car moves with its 300 Hz siren. An innocent bystander stands between the police car and a warehouse that is in the vicinity. How fast must the police car be moving if the pitch heard by the bystander is higher than the true frequency by 10 percent? Assume air temperature to be 20 degrees Celsius. (DOPPLER’S EFFECT OF SOUND)
- Two identical magnets with pole strengths of 120 amp-m, are parallel and are 8 cm apart. What force is exerted by the upper magnet on the lower magnet if the north pole of the upper magnet is opposite the south pole of the other? (COULOMB’S LAW OF MAGNETISM)
- A stone is dropped from a high altitude and 3.0 s later, another is projected vertically downward with a speed of 150 ft/s. When and where will the second overtake the first? (FREE FALL)
- A body falls from a railroad overpass that is 36 ft high into the path of a train that is approaching the overpass with uniform speed. If the body falls when the train is 50 ft away from the overpass and the body hits the ground just as the train arrives at the spot, how fast is the train moving? (10 pts) (MOTION)
- Two blocks A and B are placed as in the figure, and connected by ropes to block C. Blocks A and B weigh 20 N each and the coefficient of kinetic frictionbetween each block and the surface is 0.40. Block C descends with an acceleration of 2 m/s2. (NEWTON’S SECOND LAW OF MOTION)
- Find the tension in the ropes.
- Find the weight of block C.
- Point charges of 2 microcoulombs are situated at three corners of a squarewhose side is 0.20 m. Find:
- Total force at the center of the square if a point charge of 1 microcoulomb is placed there.
- Total electric field at the center of the square. (COULOMB’S LAW OF ELECTRICITY)
- A cave explorer is surveying a cave. He follows a passage 100 meters straight east, then 50 meters in a direction 30 degrees west of north, then 150 meters in 45 degrees west of south. After a fourth unmeasured displacement, he finds himself back where he started. Determine the fourth displacement. What is the total displacement of the cave explorer? (VECTOR ANALYSIS)
- Block A in the figure weighs 100 N. The coefficient of static friction between the block and the surface on which it rests is 0.30. The weight W is 20 N and the system is in equilibrium. Find a) the friction force exerted on A. b) Maximum weight W for which the system will remain in equilibrium. (EQUILIBRIUM)
- Two blocks A and B are placed in the figure, and connected by ropes to block C. Blocks A and B weigh 20 N and block C weighs 40 N. Block C descends with constant velocity. What is the coefficient of friction between the surfaces assuming it is common for all these surfaces? (EQUILIBRIUM)