GED Science Preparation Course: Physical science: energy, motion and matter

1. Pergunta 1 de 18

   A ball rests on top of a shelf. What kind of energy does it have because of its position?

   • APotential energy
   • BNuclear energy
   • CKinetic energy
   • DSound energy
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   Resposta: A. Potential energy

   A raised object stores gravitational potential energy. It gains kinetic energy only when it moves.

2. Pergunta 2 de 18

   What energy changes happen in a battery-powered flashlight?

   • AElectrical → chemical → nuclear and heat
   • BLight → chemical → sound and motion
   • CHeat → light → chemical
   • DChemical → electrical → light and heat
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   Resposta: D. Chemical → electrical → light and heat

   The battery stores chemical energy, which becomes electrical energy, then light and some heat in the bulb.

3. Pergunta 3 de 18

   A car engine uses fuel energy, but much of it becomes heat. What happens to the total amount of energy?

   • AIt increases because the car moves
   • BIt is destroyed inside the engine as fuel burns
   • CIt stays the same; it only changes form
   • DIt turns into mass
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   Resposta: C. It stays the same; it only changes form

   Energy cannot be created or destroyed. Some always changes into less useful heat.

4. Pergunta 4 de 18

   A metal spoon in hot soup gets hot at the handle. How did the heat travel?

   • AConvection
   • BEvaporation
   • CConduction
   • DRadiation
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   Resposta: C. Conduction

   Conduction is heat transfer by direct contact, through the metal from the hot end to the cool end.

5. Pergunta 5 de 18

   How does heat from the Sun reach Earth through empty space?

   • ACondensation
   • BConduction
   • CConvection
   • DRadiation
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   Resposta: D. Radiation

   Radiation travels as electromagnetic waves and needs no matter, so it can cross space.

6. Pergunta 6 de 18

   You squeeze an instant cold pack and it gets cold. What kind of reaction is happening?

   • ANuclear
   • BCombustion
   • CExothermic
   • DEndothermic
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   Resposta: D. Endothermic

   An endothermic reaction absorbs heat from its surroundings, so it feels cold.

7. Pergunta 7 de 18

   Which is a renewable energy source?

   • ACoal
   • BOil
   • CWind
   • DNatural gas
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   Resposta: C. Wind

   Wind is replaced naturally. Coal, natural gas and oil are fossil fuels that run out.

8. Pergunta 8 de 18

   Which type of electromagnetic wave has the most energy?

   • AVisible light
   • BInfrared
   • CRadio waves
   • DGamma rays
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   Resposta: D. Gamma rays

   From low to high energy: radio, microwaves, infrared, visible, ultraviolet, X-rays, gamma rays. Higher frequency means more energy.

9. Pergunta 9 de 18

   A runner covers 400 m in 80 seconds. What is her average speed?

   • A0.2 m/s
   • B320 m/s
   • C32,000 m/s
   • D5 m/s
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   Resposta: D. 5 m/s

   Speed = distance ÷ time = 400 ÷ 80 = 5 m/s.

10. Pergunta 10 de 18

    A car speeds up from 0 to 20 m/s in 4 seconds. What is its acceleration?

    • A80 m/s²
    • B0.2 m/s²
    • C5 m/s²
    • D16 m/s²
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    Resposta: C. 5 m/s²

    Acceleration = change in speed ÷ time = (20 − 0) ÷ 4 = 5 m/s².

11. Pergunta 11 de 18

    A 1,200 kg car moves at 15 m/s. What is its momentum?

    • A18,000 kg·m/s
    • B80 kg·m/s
    • C1,215 kg·m/s
    • D1,185 kg·m/s
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    Resposta: A. 18,000 kg·m/s

    Momentum = mass × velocity = 1,200 × 15 = 18,000 kg·m/s.

12. Pergunta 12 de 18

    What force is needed to give a 50 kg cart an acceleration of 2 m/s²?

    • A25 N
    • B48 N
    • C100 N
    • D52 N
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    Resposta: C. 100 N

    Newton's second law: force = mass × acceleration = 50 × 2 = 100 N.

13. Pergunta 13 de 18

    A rocket pushes hot gas down, and the rocket moves up. Which law explains this?

    • ANewton's first law
    • BNewton's third law
    • CThe law of superposition
    • DThe 10% rule
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    Resposta: B. Newton's third law

    Newton's third law: every action has an equal and opposite reaction.

14. Pergunta 14 de 18

    A worker lifts a box with a force of 200 N through a height of 3 m in 10 seconds. What is the worker's power?

    • A2,000 W
    • B600 W
    • C60 W
    • D6,000 W
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    Resposta: C. 60 W

    Work = 200 × 3 = 600 J. Power = work ÷ time = 600 ÷ 10 = 60 W. 600 is the work, not the power.

15. Pergunta 15 de 18

    A block has a mass of 60 g and a volume of 75 mL. Water's density is 1 g/mL. What is the block's density, and will it float?

    • A0.8 g/mL; it sinks
    • B0.8 g/mL; it floats
    • C1.25 g/mL; it floats
    • D1.25 g/mL; it sinks
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    Resposta: B. 0.8 g/mL; it floats

    Density = 60 ÷ 75 = 0.8 g/mL. It is less dense than water, so it floats. 1.25 comes from dividing volume by mass.

16. Pergunta 16 de 18

    In the balanced equation 2H₂ + O₂ → 2H₂O, how many hydrogen atoms are on the product side?

    • A6
    • B2
    • C3
    • D4
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    Resposta: D. 4

    In 2H₂O, multiply the coefficient by the subscript: 2 × 2 = 4 hydrogen atoms, the same as the 4 in 2H₂.

17. Pergunta 17 de 18

    In a sealed bag, 10 g of baking soda reacts with 50 g of vinegar. Gas forms, but nothing leaves the bag. What is the total mass after the reaction?

    • A60 g
    • BMore than 60 g, because gas formed
    • C40 g
    • D50 g
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    Resposta: A. 60 g

    Mass is conserved in a chemical reaction. Nothing escaped, so the total stays 10 + 50 = 60 g.

18. Pergunta 18 de 18

    An astronaut has a mass of 70 kg on Earth. What is her mass on the Moon?

    • AAbout 420 kg
    • BAbout 12 kg
    • C0 kg
    • D70 kg
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    Resposta: D. 70 kg

    Mass is the same everywhere. Her weight (the pull of gravity) is less on the Moon, but her mass is not.

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O exame real: 145 on a 100–200 scale