Newton's law of gravitation and field strength

Question 1

Who first published the law of universal gravitation?

• A. Johannes Kepler
• B. Galileo Galilei
• C. Isaac Newton
• D. Albert Einstein

Question 2

Calculate the gravitational field strength at the surface of the Moon, in N/kg. Mass = 7.35 × 10²² kg, radius = 1.74 × 10⁶ m, G = 6.67 × 10⁻¹¹ N m²/kg². (g = G M ÷ r²; give 1 decimal place)

Answer N/kg

Question 3

The distance between two masses is multiplied by 3. By what factor does the gravitational force between them change? (F = G m₁ m₂ ÷ r²; give 4 decimal places if needed)

Answer 

Question 4

Who first published the law of universal gravitation?

• A. Isaac Newton
• B. Albert Einstein
• C. Galileo Galilei
• D. Johannes Kepler

Question 5

Calculate the gravitational field strength at the surface of the Moon, in N/kg. Mass = 7.35 × 10²² kg, radius = 1.74 × 10⁶ m, G = 6.67 × 10⁻¹¹ N m²/kg². (g = G M ÷ r²; give 1 decimal place)

Answer N/kg

Question 6

One of two masses is multiplied by 4 and the distance stays the same. By what factor does the gravitational force change? (F = G m₁ m₂ ÷ r²)

Answer 

Question 7

Why is the value of g slightly smaller at the top of a high mountain?

• A. You are slightly further from Earth's centre
• B. It is colder
• C. There is less air
• D. Mountains have less mass

Question 8

Calculate the gravitational field strength at the surface of Jupiter, in N/kg. Mass = 1.9 × 10²⁷ kg, radius = 6.99 × 10⁷ m, G = 6.67 × 10⁻¹¹ N m²/kg². (g = G M ÷ r²; give 1 decimal place)

Answer N/kg

Question 9

One of two masses is multiplied by 2 and the distance stays the same. By what factor does the gravitational force change? (F = G m₁ m₂ ÷ r²)

Answer 

Question 10

Why do all objects near Earth's surface fall with the same acceleration (ignoring air)?

• A. A larger mass feels a larger force, but also needs more force to accelerate, so a = g for all
• B. Gravity does not depend on mass
• C. Light objects are pulled harder
• D. Heavier objects feel no extra force

Question 11

Calculate the gravitational field strength at the surface of Jupiter, in N/kg. Mass = 1.9 × 10²⁷ kg, radius = 6.99 × 10⁷ m, G = 6.67 × 10⁻¹¹ N m²/kg². (g = G M ÷ r²; give 1 decimal place)

Answer N/kg

Question 12

The distance between two masses is multiplied by 3. By what factor does the gravitational force between them change? (F = G m₁ m₂ ÷ r²; give 4 decimal places if needed)

Answer 

Question 13

Gravitational force follows an "inverse square law". What does this mean?

• A. Distance has no effect
• B. Doubling the distance halves the force
• C. Doubling the distance makes the force one quarter as strong
• D. Doubling the distance doubles the force

Question 14

Calculate the gravitational field strength at the surface of the Moon, in N/kg. Mass = 7.35 × 10²² kg, radius = 1.74 × 10⁶ m, G = 6.67 × 10⁻¹¹ N m²/kg². (g = G M ÷ r²; give 1 decimal place)

Answer N/kg

Question 15

The distance between two masses is multiplied by 3. By what factor does the gravitational force between them change? (F = G m₁ m₂ ÷ r²; give 4 decimal places if needed)

Answer 

Question 16

Who first published the law of universal gravitation?

• A. Galileo Galilei
• B. Isaac Newton
• C. Albert Einstein
• D. Johannes Kepler