Question

A block of mass 40 kg slides over a surface, when a mass of 4 kg is suspended through an inextensible massless string passing over a frictionless pulley as shown below.
The coefficient of kinetic friction between the surface and block is 0.02. The acceleration of the block is (Given g = 10 ms–2)

• A. 1 ms-2
• B. $\frac{1}{5}$ ms–2
• C. $\frac{4}{5}$ ms–2
• D. $\frac{8}{11}$ ms–2

Answer 1

Answer: (D)

$\frac{8}{11}$ ms–2

Answer 2

The correct answer is (D) : $\frac{8}{11}$ ms–2

= 0.02 × 400
= 8 N
Let the acceleration is a as shown then.
40 – T = 4 a
T – 8 = 40 a
$⇒ a = \frac{32}{44} = \frac{8}{11} m/s²$