Universal Law of Gravitation MCQs

Q1. Two cargo ships float side by side in a calm harbour. If their masses are 1000 kg and 2000 kg and their centres are 5 m apart, what gravitational force does each exert on the other?

• A.1.33e-4 N
• B.8e-9 N
• C.2.67e-5 N
• D.5.34e-6 N

Answer: D. 5.34e-6 N

By the universal law of gravitation F = G*m1*m2/r^2 = (6.67e-11)*(1000)*(2000)/(5)^2 = 5.34e-6 N.

Q2. Two cargo ships float side by side in a calm harbour, with masses 500 kg and 500 kg separated by 2 m. What is the force of gravity between them?

• A.8.34e-6 N
• B.4.17e-6 N
• C.1.67e-8 N
• D.1.67e-5 N

Answer: B. 4.17e-6 N

By the universal law of gravitation F = G*m1*m2/r^2 = (6.67e-11)*(500)*(500)/(2)^2 = 4.17e-6 N.

Q3. Two cargo ships float side by side in a calm harbour. Given masses of 10000 kg and 10000 kg and a centre-to-centre gap of 10 m, find the mutual gravitational pull?

• A.6.67e-4 N
• B.1.33e-8 N
• C.6.67e-3 N
• D.6.67e-5 N

Answer: D. 6.67e-5 N

By the universal law of gravitation F = G*m1*m2/r^2 = (6.67e-11)*(10000)*(10000)/(10)^2 = 6.67e-5 N.