Question

A man pushed the box with a force of 20 N. The mass of the box doubled, but he still pushed with a force of 20 N.

Answer 1

Answer:

Option (c) Acceleration is 1/2x the original acceleration

Explanation:

To know the the correct answer to the question, we shall determine the acceleration of the box in each case.

Case 1:

Mass (m) = m

Force (F) = 20 N

Acceleration 1 (a₁) =?

F = ma₁

20 = m × a₁

Divide both side by m

a₁ = 20 / m

Case 2:

Mass (m) = 2m

Force (F) = 20 N

Acceleration 2 (a₂) =?

F = ma₂

20 = 2m × a₂

Divide both side by 2m

a₂ = 20 / 2m

a₂ = 10 / m

Finally, we shall determine the acceleration of the box after the mass was doubled. This can be obtained as illustrated below:

Acceleration 1 (a₁) = 20 / m

Acceleration 2 (a₂) = 10 / m

a₂ : a₁ = 10 / m : 20 / m

a₂ / a₁ = 10 / m ÷ 20 / m

a₂ / a₁ = (10 / m) × (m / 20)

a₂ / a₁ = ½

Cross multiply

a₂ = ½a₁

Thus, the acceleration of the box after the mass was doubled is ½ times the original acceleration.