K-12 Exam 4th Quarter Science 9

LEANDRO G. JAPOS NATIONAL HIGH SCHOOL FOURTH QUARTER EXAM SCIENCE GRADE 9 For questions 1 and 2, refer to the table below: 12. Which of the following happens to a coconut that falls freely? a. Loses potential energy and gains kinetic energy. b. Loses both potential energy and kinetic energy. c. Gains potential energy and loses kinetic energy. d. Gains both potential energy and kinetic energy.

1.

2.

3.

4.

5.

6. 7.

8.

9.

10

11.

In the table above, what i s the momentum of the jeepney? a. 6,000 kg m/s c. 20,000 kg m/s b. 40,000 kg m/s d. 3,000 kg m/s Which has greater momentum, the jeepney or the motorcycle? a. jeepney c. both have the same momentum b. motorcycle d. cannot be determined Two identical cars are travelling along EDSA. Which of the two cars would have a greater momentum? a. the slower car c. both have the same momentum b. the faster car d. cannot be easily determined

13.

14.

A 25-kg girl is riding a 5-kg with a velocity of 5 m/s the East. What is the total momentum of a girl and a bike together? a. 100 kg m/s b. 125 kg m/s c. 150 kg m/s d. 200 m/s Which of the following is a necessary condition for the total momentum of a system to be conserved? a. Kinetic energy must not change. b. No net external force acts on the system. c. The system must be at rest. d. Only the force of gravity acts on the system For numbers 6 and 7 the given data are: Two 0.5 kg balls approach each other with the same speed of 1.0 m/s. What is the total momentum of the system before collision? a. 0 b. 0.50 kg m/s c. 1.0 kg m/s d. -1.0 kg m/s If there is no external force acting on the system, what the total momentum of the system after collision? a. 0 b. 0.50 kg m/s c. 1.0 kg m/s d. -1.0 kg m/s A lady tennis player hits an approaching ball with a force of 750 N If she hits the ball in 0.002 s, how much impulse is imparted to the tennis ball? a. 0 N s b. 1.5 N s c. 3.0 N s d. 6.0 Ns Which sequence of energy transformation best describes what happens when you switch on your battery-run radio? a. Mechanical Energy Electrical Energy Sound Energy b. Mechanical Energy Chemical Energy Sound Energy c. Chemical Energy Electrical Energy Sound Energy D. Chemical Energy Mechanical Energy Sound Energ

15.

In which case is there a decrease in gravitational potential energy? a. Amada stretches horizontally a rubber band. b. A car ascends a steep p arking ramp. c. Pamela’s puppy jumps down the chair. d. Water is forced upward through a pipe. A picture frame falls off the wall. Considering the presence presence of air, how does the kinetic energy (K) just before striking the floor compare to the potential energy (P) at its hanging point? a. K is equal to P. b. K is greater than P. c. K is less than P. d. It is impossible to tell.

21.

16.

17.

18.

19.

20.

22.

What is the energy of a motorcycle moving slowly at the top of a hill? a. entirely kinetic c. entirely gravitational b. entirely potential d. both kinetic and potential Which is a necessary condition for the total momentum of a system to be conserved? a. Kinetic energy must not change. b. No external force is present. c. An object must be at rest. d. Only the force of gravity acts on the system. Which event is explained in the sequence of energy changes shown in the diagram below?

a. a headlight is on c. electric current powers a flat iron b. a turbine spins d. gasoline burns to run a jeepney Which event illustrates the direct transformation of potential to kinetic energy? a. A basketball player catches a flying ball. b. A Kalesa moves from rest. c. Kathy’s arrow is released from its bow. d. The spring mechanism of a toy is rotated until it locked. The wind-up toy that is fully wound and at rest possesses  ___________________.  ___________________. A. kinetic but no potential energy B. potential but no kinetic energy C. both potential and kinetic energy in equal amounts D. neither potential nor kinetic energy The impulse experienced by a body is equal to the change in its: a. Velocity b. Kinetic energy c. Momentum d. Potential energy Which among the forms of energy is considered a potential energy? a. chemical energy b. radiant energy c. sound energy d. thermal energy A torchlight fell from a watch watch tower. The potential energy of the torchlight at the highest point compared to its kinetic energy at the lowest point is _______ a. lesser. b. equal. c. greater. d. not related. Which event illustrates the direct transformation of potential to kinetic energy? a. A volleyball player blocks an incoming ball. b. A sleeping cow stirs awake. c. The wide-open spring spring door closes slowly. d. The spring of a broken toy toy shoots up. Which of the following happens to raindrops? a. Loses potential energy and gains kinetic energy. b. Loses both potential energy and kinetic energy. c. Gains potential energy and loses kinetic energy. d. Gains both potential energy and kinetic energy.

23.

24.

25.

26.

Francis stretched a rubber band five times. After that, he observed that the rubber band felt warmth. Did the rubber band gain heat? a. No, it is not evident. b. Yes, the rubber band felt warmth means it gain ed heat c. Yes, the rubber band felt warmth means it loss heat. d. No, temperature is not related to a gain or loss of heat. What is commonly used as ref rigerant for most of the refrigerators? a. Liquid that is easy to solidify. b. Liquid that is hard to solidify. c. Gas that is easy to liquefy. d. Gas that is hard to liquefy

34. .

How can air conditioning unit functions as heater during col d days and cooler during hot days? 1. It cools the inside of the house and heats the outside. 2. It takes heat from the air outside to warm the in side. a. 1 only b. 2 only c. 1 and 2 only d. None of them

35.

What is the function of a heat engine? a. It converts chemical energy to mechanical energy. b. It converts thermal energy to mechanical energy. c. It converts mechanical energy to chemical energy. d. It converts thermal energy into chemical energy.

How does water from the deep well move upward? a. It occurs naturally. b. It uses water heat pump. c. It is a spontaneous process. d. It flows from higher temperature to cooler temperature.

36. What causes thermal pollution?

Is it possible to change the temperature of a glass of water by stirring the water, even though the glass is insulated from its surroundings? a. No, stirring will not affect the temperature of the water. b. No, insulation prevents the change of temperature of the water. c. Yes, stirring the water increases its internal energy causing the increase of its temperature. d. Yes, stirring the water decreases its internal energy causing the decrease of its tempera

37. In which of the following units is electrical consumption

Modified True or False. Study each statement. Write True if it is correct and if not, change the underline word/s to make it true. 27.

Heat engine is any device that converts thermal energy into mechanical work.

28.

In every heat engine, all of the heat can be converted into work.

29.

Mechanical work takes place in the piston of a gasoline engine.

30.

There is no ideal heat engine, m aking some heat exhaust in the environment.

31.

Thermal pollution is brought about by the accumulated exhaustion of heat from diesel, gasoline and industrial engines.

32.

What energy transformation takes place in a generator? a. electrical to mechanical c. mechanical to electrical b. heat to mechanical d. chemical to mechanical

33.

In which case will electric current be induced in a coil of wire? a. when it is connected to a galvanometer b. when a magnet is held stationary inside the coil c. when a magnet is rapidly inserted into and out of the coil d. when a magnetic compass is held beside it

a. Exhaust of different vehicles. b. Exhaust from different industrial engines. c. Degradation of water. d. All of them

measured by electric companies consumption in our homes? a. kilowatt b. volt c. megawatt

four

our

household

d. kilowatt  hour

38. In power stations generating electricity, power is measured in  _________. a. joule

b. kilojoule

c. kilowatt

d. megawatt

39.

Shayne turned on a lamp switch in her room. Which of the following is the correct path of electrical power that can be traced back to the source? a. power plant transmission substations distribution substations residences b. transmission substations power plants residences distribution substations c. residences distribution substation power plants transmission substations d. distribution substations transmission substations power plants residences

40.

You made an electric motor in school. When you tested it in using 4 dry cells, the armature turned very fast. What should you do to make it turn slower? a. use a bigger magnet b. remove one of the dry cells c. increase the number of turns in the coil of wire d. decrease the distance between the magnetic poles

41.

If a 100 W light bulb is lit for 8 hours each day for 20 days in a month. How many kilowatt-hours will the bulb consume? a. 16 b. 160 c. 1600 d. 16000

For nos. 42-51 , complete the table below and show your complete solution. A 2-kg stone dropped on top of a hill and reached the ground after 1s. Time (s)

Height (m)

Velocity (m/s)

PE (J)

KE (J)

TME PE + KE

0 1

42.___

43.____

44.___

45. ___

46.___

47.___

48.____

49.___

50.____

51.___

39.

40.

46. 40. 41. 42. 43.

47 48. 49. 50.