Question

Two blocks connected by a massless string slide down an inclined plane having angle of inclination as 37⁰. The masses of two blocks are 4 kg and 2 kg with μ, as 0.75 and 0.25 respectively.

• A. The common acceleration of two masses is 1.3 ms^-2 and tension in string is 5.3 N.
• B. Tension in the string is 14.9 N.
• C. Acceleration of the mass is 3 N.
• D. The acceleration of masses is 5.3 ms^-2 and tension in the string is 1.3 N.

Answer 1

Answer: (A)

The common acceleration of two masses is 1.3 ms^-2 and tension in string is 5.3 N.

Answer 2

For mass M₁

T + M₁g sin 37 - μ₁M₁g cos 37 = M₁a ……… (i)

and for mass M₂

M₂g sin 37 – T - μ₂ M₂g cos 37 = M₂a ……… (ii)

Adding the substituting the given values, we get

2g × 0.6 + 4g × 0.6 – 0.25 × 2g × 0.8 – 0.75 × 0.8 = (4 + 2)a

g (1.2 + 2.4 – 0.4 – 2.4)6a

or a = 1.3 ms^-2

Using (ii)

2 9.8 × 0.6 – T – 0.25X 2 × 9.8 × 0.8 = 2 X 13

or T = 11.76 – 3.98 – 2.6

= 5.29 N