Force
1 Marks Question
 What is the value of 'g' in the equatorial region and polar region of the earth?
 The value of 'g' of the earth on equatorial region is 9.78 m/s^{2} and polar region is 9.83 m/s^{2}.
 What is the value of acceleration due to gravity 'g' at the center of the earth?
 The value of acceleration due to gravity 'g' at the center of the earth is 0 m/s^{2}.
 What is acceleration due to gravity?
 Acceleration produced in a freely falling object due to the presence of gravity is called acceleration due to gravity. Its SI unit is m/s^{2}.
 Write the value of acceleration due to gravity on the surface of the moon in S.I. unit.
 The value of acceleration due to gravity on the surface of the moon is 1.66 m/s^{2}
 What is freefall?
 The fall of a body under the effect of gravity in the absence of external resistance is called freefall.
 What is gravity?
 The force of an object attracting another object to its center is called gravitational force.
 Write the formula to find the weight of an object.
 The formula to find the weight of an object is w = m x g.
 What is the value of universal gravitational constant (G)?
 The value of universal gravitational constant (G) is 6.67 × 10^{11} Nm^{2}/kg^{2}.
 State Newton's universal law of gravitation.
 The gravitational force of attraction between any two heavenly bodies is directly proportional to the product of their masses i.e. f ∝ m1.m2 and inversely proportional to the square of distance between their centers i.e. f ∝ 1/r^{2}.
 What is gravitational constant? Also write its SI unit.
 The force of attraction existing between two unit masses separated by a unit distance is called gravitational constant. Its SI unit is Nm^{2}/kg^{2}.
 What is gravitation (gravitational force)?
 The mutual force of attraction between two bodies is called gravitation or gravitational force.
 The value of universal gravitational constant is 6.67 × 10^{11} Nm^{2}/Kg^{2}. What does it mean?
 The value of universal gravitational constant (G) is 6.67 × 10^{11} Nm^{2}/Kg^{2}, it means that 1 kg of substance attracts 1 kg of other substance with 6.67 × 10^{11} N force from unit distance.
 What is weightlessness?
 When a body falls freely under the effect of gravity, the weight of the body appears to be zero. This state of the body is weightlessness.
 In which condition will the acceleration due to gravity of parachute becomes zero?
 When upthrust of air is equal to the force of gravity of the earth on the falling parachute, the acceleration due to gravity of parachute becomes zero.
 In which direction does the force of gravity act?
 The force of gravity acts towards the center of heavenly body.
 Write one effect seen on ocean or sea due to gravitation of the moon and the sun.
 Tide is the effect seen on the ocean or sea due to the gravitation of the moon and the sun.
 Where does the weight if a body is maximum on the surface of the earth?

We know,
weight = mass * acceleration due to gravity
w ∝ g (m is constant)
The value of g is maximum at pole (9.83 m/s^{2}). So, the weight of a body is maximum on the polar region of the earth.  What are the two factors that affect the force of gravitation?

Two factors that affect the force of gravitation are:
 Product of the masses of bodies.
 Distance between bodies from their center.
 What is the value of acceleration due to gravity at the equatorial region of the earth? Write in SI unit.
 The value of acceleration due to gravity at the equatorial region of the earth is 9.78 m/s^{2}. Its SI unit is m/s^{2}.