According to Newton's Second Law, what happens to the force if mass doubles while acceleration stays the same?

According to Newton's Second Law, what happens to the force if mass doubles while acceleration stays the same?

• A. It quadruples
• B. It stays the same
• C. It doubles
• D. It halves

Answer: (C)

When acceleration is kept constant, force is directly proportional to mass because F = m a. If mass doubles while a stays the same, the product m a doubles, so the force must double. Think of pushing a cart: with the same speed of acceleration, a heavier cart requires a stronger push, exactly doubling the force if the mass doubles. A quadruple force would require something else to change (like acceleration or mass changing by more than a simple doubling); the force staying the same would mean mass or acceleration didn’t change; halving the force would require mass to halve or acceleration to drop. So the force doubles.

When acceleration is kept constant, force is directly proportional to mass because F = m a. If mass doubles while a stays the same, the product m a doubles, so the force must double. Think of pushing a cart: with the same speed of acceleration, a heavier cart requires a stronger push, exactly doubling the force if the mass doubles. A quadruple force would require something else to change (like acceleration or mass changing by more than a simple doubling); the force staying the same would mean mass or acceleration didn’t change; halving the force would require mass to halve or acceleration to drop. So the force doubles.