Physics – Second Semester Midterm Review Day 1 Review

1. Physics – Second Semester Midterm Review Day 1 Review 1. A car decelerates from 20 m/s to a stop in four seconds. What was the magnitude and direction of the car’s acceleration? 2. A row boat is paddled in the direction due West at 3 m/s across a river that flows South at 4 m/s. A person watching from the shore sees the boat moving diagonally at what speed? 3. A car traveling at 10 m/s speeds up to a speed of 30 m/s in 10 seconds. How far does it move over this time interval?

2. 4. A student does an experiment to measure the acceleration of a falling object, which is 9.8 m/s2. The student obtains an experimental value of 14.6 m/s2. The reason for this variation is most likely due to a. human error b. air resistance c. local fluctuations in gravity d. the mass of the object 5. A ball is thrown straight up and then falls straight back down. When it attains maximum height, the ball’s velocity is a. equal to displacement b. equal to displacement divided by time. c. at its maximum d. at its minimum 6. The picture shows two objects that were dropped and recorded with a stroboscopic camera. The best explanation for the results is that object A a. has less air resistance b. was dropped from a greater height c. has a greater mass d. accelerated more slowly

3. 7. According to Newton’s _____ law, an object at rest stays at rest, an object in motion stays with that motion until a net force acts on it. 8. According to Newton’s _____ law, a net force on an object causes the object to accelerate in the same direction as the force (F=ma). 9. According to Newton’s _____ law, for every action force there is an equal an opposite reaction force. 10. A soccer player kicks a 0.5 kg stationary ball with a force of 50 N. What is the force of the player’s foot? a. 0 N b. 25 N c. 50 N d. 100 N 11. An object has a mass of 1.5 kg. What is its weight on earth? What is its mass on the moon? What is its weight on the moon (g = 1.67 m/s2)? 12. A 10 N force and a 15 N force are acting from a single point in opposite directions. What additional force must be added to produce equilibrium? a. A 5 N force acting in the same direction as the 10 N force. b. A 5 N force acting in the same direction as the 15 N force. c. A 10 N force acting in the same direction as the 10 N force d. A 25 N force acting in the same direction as the 15 N force.

4. 13. A block has a mass of 1.5 kg. A force of 7.5 N is required to get it sliding on a rough surface. What is the coefficient of static friction? 14. The figure shows a block that is pulled along the floor. According to the figure, what is the acceleration of the block? 15. A communication satellite in a circular orbit around the earth. If the speed of the satellite is constant, the force acting on the satellite a. is zero b. is decreasing c. points toward the corner of the earth at all times. d. points in the direction that the satellite is moving.

5. 16. A 2000 kg car drives at 40 m/s around a circular track with radius of 100 m. What is the magnitude and direction of the centripetal force acting on the car? What agent exerts the force on the car? 17. If the track was icy, so that there was no friction, what is the path of the car? 18. A 500 N person sits 1.5 meters from the center of a see saw. Where does his 700N brother need to sit to balance the see saw?

6. 19. A 10 kg block is sliding down a 30 incline plane. What is the magnitude of the parallel component of the gravity force, Fg||? What is the magnitude of the perpendicular component of the gravity force, Fg? What is the value of the normal force?

7. Day 2 Review 20. Two identical masses, of mass m, are set a distance, d, apart. They obey the law of universal gravitation: F = G m.m By how much will the gravitational force change d2 if both masses are doubled and the distance between them is tripled? 21. A hockey puck has a mass of 0.05 kg and is at rest. A hockey player makes a shot, exerting a force of 25 N on the puck, bringing it to a speed of 20 m/s. What is the change in momentum of the puck? How much time was the stick in contact with the puck? 22. In which of the following situations is work done in a physics sense, and by whom? a. a mass is lifted off the ground b. a mass slides horizontally at c. a mass is dropped a constant speed across a frictionless surface

8. 23. What is the correct formula for each of the following: a. Work = _____ b. PE = _____ c. KE = _____ d. p = _____ 24. A high diver steps off a diving platform that is 10 meters above the water. If no air resistance is present, during the fall there will be a decrease in the driver’s a. gravitational potential energy b. total mechanical energy c. kinetic energy d. momentum 25. A 2.0 kg mass is moving with a speed of 3.0 m/s. What is the kinetic energy of the mass? a. 1.5 J b. 6.0 J c. 9.0 J d. 12.0 J 26. A 50 kg firefighter is high up on a ladder. When the firefighter descends 5 meters lower, the firefighter‘s gravitational potential energy will decrease by a. 0.194 joules b. 5.10 joules c. 490 joules d. 2450 joules

9. 27. A 50 kg skateboarder starts at the top of a ramp 3 meters tall, as measured straight up from the ground, as pictured. How fast is he going at the bottom of the ramp? 28. A child is on a sled moving down a hill at 20 meters/second. The combined mass of the sled and child is 100 kilograms. The momentum of the child and the sled is a. 5 kg.m/s b. 20 kg.m/s c. 1000 kg.m/s d. 2000 kg.m/s

10. 29. A 0.5 kg lab cart rolls at a constant speed of 2.5 m/s and collides with a 1.0 kg cart initially at rest. a. If the carts stick together, what is their final speed? b. If the carts do not stick together, and the 1.0 kg cart moves away with a speed of 1.5 m/s, what is the final speed of the 0.5 kg cart? 30. A student pushes a 250 N desk across a rough floor, at a constant speed. The student applies a force of 50 N. The desk moves 5 meters in a time of 10 seconds. a. How work does the student do on the desk? b. How much power does the student generate?

11. Day 3 31. A submarine has a viewing window that is a square 30 cm per side. If there is a force of 36,000 N acting on it, what is the pressure at that depth? 32. The pressure of a gas inside a closed, rigid container will increase when the gas temperature increases. The pressure of the gas increases because the a. density of the gas decreases b. rate of collisions of gas molecules with the surface increases c. container expands in size when heated d. gas molecules bond together to form more massive molecules

12. 33. When the gasoline inside a car engine explodes it releases a tremendous amount of heat energy (Q) into the system. What are the two forms of energy this Q turns into? 34. When I was 5 years old, my favorite movie was Star Wars. I loved the scenes where the X-Wing fighters were fighting the evil TIE fighters, flying through outer space. The sounds of the fighters and the guns were amazing! But you guys aren’t so easily amused. What was wrong with these scenes? 35. What are the similarities and differences between radio waves, visible light rays, and X-Rays, in terms of speed, type of wave (transverse or compressional), wavelength, frequency and destructive energy.

13. 36. Explain the types of waves used when you are talking to your BFF over your cell phone. 37. The frequency of piano note is 512 Hz. If the speed of sound in air is 343 m/s, what is the wavelength of the sound wave? 38. How are frequency and period related? 39. A couple years ago I went to the California Speedway to watch the Indy cars race. From my seat, the cars somehow sounded different as they approached compared to after they passed. My wife asked me why the engines always changed sound as they passed by. What would you have told her? (Hopefully your answer includes the ________ Effect, and something about the wavelength, frequency, and pitch of the car as it approaches and passes)

14. 40. Objects appear different in size and shape in a container of water due to a. refraction of the light waves b. interference of the water and light waves c. polarization of the light waves d. diffraction of the light waves 41. What color is produced when blue light and green light are added together? 42.  A light ray is incident on water at a 30 angle as pictured. If the index of refraction for air is 1.0, and for water is 1.33, find the angle of refraction.

15. 43. Draw the electric field surrounding a positive charge. Draw the electric field surrounding a negative charge. 44. I have a 12 V battery, some wires, and two 6 Ω resistors. (Think about series and parallel) a. Could you please wire me a circuit where the current would be as small as possible? b. Could you wire me a circuit where the current is as large as possible? c. How much power does the 12 V battery produce in each circuit? d. If a 12 V battery typically contains a chemical reaction with 24,000 J of energy available, how long will the battery theoretically last?