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Quiz Chapter 3: Gravitation

10 questions · Form 4 Physics Bab 3: Gravitation

10 questions · plays in fullscreen

Full Question List & Answer Key

Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.

1. According to Kepler's Third Law, if the orbital radius of satellite A is 4 times that of satellite B, how many times greater is the orbital period of satellite A compared to satellite B?

  1. 2 times
  2. 16 times
  3. 64 times
  4. 8 times
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Answer: D

T² ∝ r³. (T_AT_B)² = (41)³ = 64. Taking the square root gives T_AT_B = √64 = 8.

2. Calculated from Earth's surface (M = 5.97 × 1024 kg, R = 6.37 × 106 m, G = 6.67 × 10-11 N m² kg-2, what is Earth's approximate escape velocity?

  1. 7.9 km s-1
  2. 11.2 km s-1
  3. 15.0 km s-1
  4. 9.8 km s-1
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Answer: B

v_e = √[2 × 6.67 × 10-11 × 5.97 × 10246.37 × 106] ≈ 11,180 m s-1 ≈ 11.2 km s-1.

3. What provides the centripetal force required to keep a satellite orbiting around the Earth?

  1. Atmospheric pressure
  2. Gravitational force between Earth and satellite
  3. Solar radiation pressure
  4. Magnetic force of the Earth
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Answer: B

The gravitational force exerted by the Earth on the satellite acts as the centripetal force maintaining the circular orbit.

4. What is the shape of planetary orbits around the Sun according to Kepler's First Law?

  1. Hyperbolic
  2. Elliptical
  3. Perfectly circular
  4. Parabolic
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Answer: B

Kepler's First Law states that all planets move in elliptical orbits with the Sun at one focus.

5. What is the main application of non-geostationary satellites like TiungSAT and RazakSAT?

  1. Direct-to-home satellite TV broadcast
  2. Earth observation and environmental sensing
  3. 24-hour fixed communications link
  4. Geostationary weather monitoring
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Answer: B

Non-geostationary satellites in lower orbits sweep across different geographical zones, making them ideal for high-resolution Earth imaging and sensing.

6. Which formula correctly gives the escape velocity, v_e, from the surface of Earth with mass M and radius R?

  1. v_e = √(GM / R)
  2. v_e = √(2GM / R)
  3. v_e = 2GM / R²
  4. v_e = √(GM / 2R)
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Answer: B

Escape velocity is derived by equating initial kinetic energy to gravitational potential energy, yielding v_e = √(2GM / R).

7. What is the orbital period of a geostationary satellite?

  1. 12 hours
  2. 48 hours
  3. 24 hours
  4. 365 days
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Answer: C

A geostationary satellite has an orbital period identical to Earth's rotation period, which is 24 hours.

8. Which of Kepler's laws states that a planet sweeps out equal areas in equal intervals of time?

  1. Kepler's First Law
  2. Kepler's Third Law
  3. Kepler's Second Law
  4. Newton's First Law
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Answer: C

Kepler's Second Law (Law of Areas) states that a line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.

9. What is the relation between linear speed v and orbital distance r for a satellite in a circular orbit?

  1. v is directly proportional to r
  2. v is directly proportional to √r
  3. v is inversely proportional to r²
  4. v is inversely proportional to √r
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Answer: D

From v = √(GM / r), the linear orbital velocity v is inversely proportional to the square root of radius r (v ∝ 1/√r).

10. Two objects of mass 50 kg and 80 kg are placed 2 m apart. Calculate the gravitational force between them. (G = 6.67 × 10-11 N m² kg-2

  1. 6.67 × 10-8 N
  2. 1.33 × 10-7 N
  3. 6.67 × 10-9 N
  4. 2.67 × 10-8 N
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Answer: A

F = G(m1)m2r² = 6.67 × 10-11 × 50 × 802² = 2.668 × 10-74 = 6.67 × 10-8 N.

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