Gravitational Force

Let the force of 2 N be and the force of 16 N be . The length of the rod is 21 cm. To find the point where the resultant acts, we use the formula for the position of the resultant force: Where: - , - Now, substituting the values: The distance from the greater force (16 N) is . Thus, the correct answer is 4 cm.

Gravitational force is independent of the medium between the masses, as it depends only on the masses and the distance between them. Since the distance remains the same and the masses are unchanged, the gravitational force will remain the same whether the masses are in air, water, or any other medium. Therefore, the correct answer is , which contradicts the given options. Hence, the gravitational force in water is still the same, and the correct choice is .

The acceleration due to gravity is given by the formula: Where: - is the gravitational constant - is the mass of the Earth - is the radius of the Earth Since the mass of the Earth remains unchanged and the radius shrinks by 4%, the new radius is . The new acceleration due to gravity is: Thus, the percentage change in is: Therefore, the correct answer is 16%.