**Physics II Semester Test**

Multiple choice: **Choose the best answer for each of the following questions. Mark your answer on the scan-tron with a #2 pencil **(2 points each)

1.When a force is exerted on an object, work is done only if the object

(a) remains stationary(b) has no momentum

(c) is heavy(d) moves

2.How much work is done if you raise a 6.0-N weight 1.5 m above the ground?

(a) 7.5 J(b) 9.0 J(c) 0.0 J(d) 4.0 J

3.It takes 40 J to push a large box 4 m across a floor. Assuming that the push is in the same direction as the displacement, what is the size of the force on the box?

(a)4 N.(b) 10 N.(c) 40 N.

(d) 160 N.(e) none of these.

4.A workwoman can lift barrels a vertical distance of 1 meter or can roll them up a 2 meter long frictionless ramp to the same elevation. If she uses the ramp, the applied force required is

(a) half as much.(b) twice as much.(c) the same.

5.Which has greater kinetic energy, a car traveling at 30 km/hr or a car with half the mass, traveling at 60 km/hr?

(a) the 30 km/hr car.(b) the 60 km/hr car.

(c) both have the same kinetic energy.

6.When an object is lifted 10 meters, it gains a certain amount of potential energy. If the same object is lifted 20 meters, its gain in potential energy is

(a) less(b) the same.(c) twice as much.

(d) four times as much.(e) more than 4 times as much.

7.A rifle recoils while firing a bullet. The speed of the rifle's recoil is small because the

(a)force against the rifle is small compared to the force on the bullet.

(b)speed is mainly concentrated in the bullet.

(c)rifle has lots of mass.

(d)momentum of the rifle is unchanged.

(e)none of these

8.In order to catch a ball, a baseball player moves his or her hand backward in the direction of the ball's motion. Doing this reduces the force of impact on the player's hand principally because it

(a)increases the impact time.

(b)decreases the impulse on the glove.

(c)decreases the change in momentum of the ball.

(d)all of the above

(e)none of the above

- The greatest change in momentum will be produced by

(a) A large force acting over a short time

(b) A large force acting over a long time

(c) A small force acting over a short time

10. Impulse can be represented by

(a) mv(b) v / t (c) F t(d) none of these answers

11. If an object moving at a rate of 20 m/s collides with a stationary object and the two objects move away together , the velocity of the combined objects will be

(a) greater than 20 m/s(b) less than 20 m/s(c) 20 m/s

12. Two moving objects collide and move apart on paths that are 120 degrees. The total momentum of the objects after the collision is _____ the total momentum before the collision.

(a) greater than.(b) equal to(c) less than

13. Rubbing two objects such as plastic and wool together creates a static charge because

(a) atoms are transferred from one object to another.

(b) electrons become more widely distributed in each object.

(c) electrons are transferred from atoms in one object to atoms in the other object.

(d) the electrons in one object are attracted to the nuclei in the other object.

14. When an electroscope is charged, its leaves spread apart because

(a) like charges attract.

(b) like charges repel and charges exert force on other charges over a distance.

(c) charges exert force on other charges over a distance.

(d) positive and negative charges spread over the metal surfaces

15. In charging by induction

(a) a neutral object can be used to separate like charges.

(b) a charged object can be used to charge a neutral object without touching it.

(c) no charges are separated.

(d) a charged object can be used to change the charge of another charged object.

16. Egg shells are held together by

(a)the gravitational force.(b)the electric force.

(c)the weak nuclear force.(d)the strong nuclear force.

17.Suppose a positive test charge was brought to a distance of 10 cm from the center of a small, hollow, charges copper ball. How would the force change if the test charge were moved to 20 cm?

(a) 4 times the force.(b) 2 times the force.

(c) 1/4 times the force.(d) 1/2 times the force.

18.Using the same copper ball described in Question 17, what is the force if the test charge is placed at the center of the hollow ball compared to its original 10 cm distant location?

(a) The same as at 10 cm.(b) 2 times the force.

(c) zero.(d) 1/2 times the force.

19.How do the signs of the charges compare in the diagram to the right?

(a)Both are negative.

(b)Both are positive.

(c)QA is negative and QB is positive.

(d)QA is positive and QB is negative.

20.What is the current in a common 100 watt light bulb when connected across a potential difference of

120 volts?

(a)12,000 amperes(b)12 amperes

(c)1.2 amperes(d)0.83 amperes

21.Compare the resistance of branch 1 with that of branch 2. A branch is a section of a circuit. The resistance of branch 1 is _____ branch 2.

(a) Four times

(b) Double

(c) The same as

(d) Half

(e) One quarter (1/4)Branch 1 Branch 2

22.What happens to the brightness of the bulbs when the switch is opened?

(a) all 3 bulbs go out

(b) A and B get dimmer, C goes out

(c) A and B get brighter, C goes out

(d) A and B remain the same, C goes out

(e) A is brighter than B, C goes out

23.Which diagram shows the proper placement of an ammeter to measure the current through bulb 2?

(a)(b)(c)(d)

24.Which diagram shows the proper placement of a voltmeter to measure the potential drop across bulb 2?

(a)(b)(c)(d)

25. A series circuit contains four resistors. The equivalent resistance (Rt) of the circuit is equal to

(a) Rt = (R1 +R2 +R3 +R4) / 4(b) Rt = 4R

(c) Rt = R1 +R2 +R3 +R4(d) 1/Rt = 1/R1 + 1/R2 + 1/R3 + 1/R4

26. A parallel circuit contains four resistors. The equivalent resistance (Rt)of the circuit is equal to

(a) Rt = (R1 +R2 +R3 +R4) / 4(b) Rt = 4R

(c) Rt = R1 +R2 +R3 +R4(d) 1/Rt = 1/R1 + 1/R2 + 1/R3 + 1/R4

27.Waves on banjo strings are _____ waves.

(a) longitudinal(b) transverse(c) surface(d) electromagnetic

28.The shortest time interval during which wave motion repeats is the

(a) wave pulse.(b) period(c) frequency.(d) wavelength.

29.The number of complete vibrations per second is the

(a) wave pulse.(b) period(c) frequency.(d) wavelength.

30.The shortest distance between two points on a wave where the wave pattern

is repeated is the

(a) period.(b) wavelength.(c) amplitude.(d) frequency.

31.The speed of any mechanical wave depends on

(a)its reflection.(b)the medium through which it travels

(c)its frequency.(d)its amplitude.

32.A musical note that is higher than another musical note has what wave property?

(a) lower frequency(b) shorter wavelength

(c) greater amplitude (d) longer period

33. Indicate the interval which represents

one full wavelength.

(a) a to c(b) b to d

(c) a to g(d) c to g

34.When a sound is made louder, which of the following features is increased?

(a) Wavelength(b) Frequency(c) Wave velocity(d) amplitude

35.Light is a(n) _____ wave.

(a) compressional(b) electromagnetic(c) mechanical

(d) longitudinal

36.Violet light has a wavelength of about

(a) 400 nm.(b) 500 nm.(c) 200 nm.(d) 700 nm.

37.The wavelength of red light is

(a) 700 nm.(b) 400 nm.(c) 500 nm.(d) 200 nm.

38.The _____ of light is a defined value.

(a) wavelength(b) frequency(c) speed(d) amplitude

39.According to the law of reflection

(a)the incident ray and the reflected ray are in different planes.

(b)the normal is parallel to the angle of reflection.

(c)the angles of reflection and incidence are equal.

(d)light rays are reflected in the same direction from a smooth surface.

40.Which of the following surfaces reflect all the wavelengths of visible light?

(a) red paper(b) blue paper(c) black paper(d) white paper

41.When light rays travel from an optically-less-dense medium into a

optically-more dense medium

(a)the angle of refraction is smaller than the angle of incidence.

(b)the refracted rays bend toward the normal.

(c)the rays travel more quickly.

(d)the angle of incidence equals the angle of refraction.

**Use the following answers for questions 42 – 46**

(a) Black(b) Magenta(c) Red(d) Yellow(e) Green

42.What is the resulting color when you add the red and blue light together?

43.What is the resulting color when you add the red and green light together?

44.What is the resulting color when you place a red and green filter in front of each other?

45.What is the resulting color when you place a cyan and green filter in front of each other?

46.What is the resulting color when you place a red and yellow filter in front of each other?

**Grading scale for the problems**

# Missed / Points / # Missed / Points / # Missed / Points

0 / 108 / 7 / 76 / 13 / 40

1 / 106 / 8 / 70 / 14 / 34

2 / 103 / 9 / 64 / 15 / 28

3 / 99 / 10 / 58 / 16 / 22

4 / 94 / 11 / 52 / 17 / 16

5 / 88 / 12 / 46 / 18 / 10

6 / 82

Choose any 18 problems to solve. Make sure you number which problems you work. Show all of your work, including equations, substitution and your answer (circled) for credit! (NO WORK NO POINTS). Extra credit for more than 18 problems solved

**For questions 1-2**, consider the diagram representing a portion of an amusement park ride. A 100 kg car has 29,400 J of Potential Energy at point A. It moves down a frictionless track and comes to a stop as it compresses a huge spring at point D.

1.How much Kinetic Energy does the car have at point “C”

2.How fast is the car moving at point “B”

**For questions 3 and 4**, Suppose the spring below has a spring constant of 50. N/m. The box has a mass of 8.0 kg and rests on a surface of negligible friction.˜

3.In the diagram above left, the spring was compressed 4.0 m. How much energy does the spring now store?

4. Suppose that all the elastic energy were transferred to the box when it was released (diagram above right). How fast would the box be moving?

5.A tennis player hitting a backhand shot exerts a 18.0 N force on the tennis ball for 0.16s. What impulse is given to the ball?

6.A 0.38 Kg kickball is rolled toward a kicker at 7.9 m/s. After the ball is kicked, its velocity is -12.8 m/s. What impulse did the kickers foot apply to the kickball?

**For questions 7 and 8** The picture throws a150 g baseball from the pictures mound toward home plate with a speed of 30.0 m/s. The batter hits the ball directly back to the picture with a speed of 40.0 m/s

7.What is the change in momentum of the ball?

8.If the bat is in contact with the ball for 5.0 X 10-3 s, what is the average force exerted on the ball during the collision of the ball with the bat?

9.Two bodies charged with -8.5 x 10-5 C are 0.17 m from each other. What force acts on each particle?

10.How far apart are two electrons if they exert a force of repulsion of 1.0 N on each other? (the charge of an electron is 1.60 X 10-19 C )

11.A charge produces as electric field of -1500 N/C in the point of space. What is the electric force on

a 5.0 x 10-6 C charge in this field?

**Consider the circuit at right for problems 12 and 13**

12.Find the total current in the circuit

13.Find the voltage drop across the 30 resistor

14. A resistance of 65 ohms has a current of

0.41-Amps through it when it is connected to the terminals of a battery. What is the voltage of the battery?

15.A sound with a frequency of 450.0 Hz travels through an alloy. A wavelength of 10.60 m is measured. What is the speed of sound in the alloy?

16.Water waves on a lake travel 5.0 m in 2.7 s. The period of oscillation

is 1.4s. What is the wave length of the water waves?

**The speed of sound in air at 20oC is 343 m/s**

17.You clap your hands while walking in a valley. The echo takes 0.450 s from one wall and 0.870 s from the other (the time is how long it takes the sound to go from the wall to your ear). How wide is the valley? ( the air temperature is 30.0o C.)

18.A tuning fork causes resonance in an air column at 25.6 cm that has a diameter of 4.60 cm. What is the frequency of the tuning fork? (the air temperature is 15.0o C.)

**The speed of an electromagnetic wave is 3X108 m/s**

19.What is the frequency of a microwave that has a wavelength of 2.9 cm?

20.The sun is 1.5 x 108 km from the Earth. How long does it take for its light to reach the Earth.