Question

On a smooth plane surface (figure) two block A and B are accelerated by up by applying a force 15 N. If mass of B is twice that of A, the force on B is

• A. 30 N
• B. 15 N
• C. 10 N
• D. 5 N

Hint:

The force on an object in a system is proportional to its mass and acceleration. Newton's second law can help calculate the force when the total force and masses are known.

Answer 1

The Correct Option is C

Step 1: Use Newton's second law.
Let the mass of block A be \( m \), and the mass of block B be \( 2m \). The total force applied is 15 N, and the acceleration of the system is given by: \[ a = \frac{F}{m_{\text{total}}} = \frac{15}{m + 2m} = \frac{15}{3m} = \frac{5}{m} \]
Step 2: Calculate the force on block B.
The force on block B is \( F_B = 2m \times a = 2m \times \frac{5}{m} = 10 \, \text{N} \).
Final Answer: \[ \boxed{10 \, \text{N}} \]