Question

A 10 kg box is pulled with a horizontal force of 50 N on a surface offering a frictional force of 20 N. What is the net acceleration of the box? (Take \( g = 10 \, \text{m/s}^2 \))

• A. 2 m/s\textsuperscript{2}
• B. 3 m/s\textsuperscript{2}
• C. 5 m/s\textsuperscript{2}
• D. 7 m/s\textsuperscript{2}

Hint:

Always subtract friction from the applied force to find the net force before using \( a = \frac{F}{m} \). Friction resists motion!

Answer 1

The Correct Option is A

Net force acting on the body is: \[ F_{\text{net}} = F_{\text{applied}} - F_{\text{friction}} = 50\, \text{N} - 20\, \text{N} = 30\, \text{N} \] Using Newton’s Second Law: \[ a = \frac{F_{\text{net}}}{m} = \frac{30}{10} = 3 \, \text{m/s}^2 \] Option (b) is incorrect because it confuses net and applied force. Option (a) is correct.