A wooden block of mass m₁ kg accelerates at 10 ms^-2 when a force of 5 N acts on it. Another block of mass m₂ kg accelerates at 20 ms^-2 when the same force acts on it. If both the blocks are tied together and the same force acts on their combination, the acceleration will be about:

Question

Question

This question was previously asked in

RRB ALP Previous Paper 19 (Held On: 30 Aug 2018 Shift 1)

Answer 1

CONCEPT:

Force: The interaction which after applying on a body changes or try to change the state of motion or state of rest is called force.
Force is denoted by F and the SI unit is Newton (N).

Force (F) = Mass (m) × acceleration (a)

Calculation:

Given that,

acceleration of mass m₁ = 10m/s²

Force on block m₁ = 5 N

acceleration of mass m₂ = 20m/s²

As Force = Mass × Acceleration

→ In 1st case according to F = m × a

5 = m₁ × 10

m₁ = ½

→ In 2nd case according to F = m × a

5 = m₂ × 20 [same force is acting in both cases, given in ques]

m₂ = ¼

→ now, as the two boxes are tied together the total mass will become

M = m₁ + m₂

= ½ + ¼ => ¾

→ According to F = M × a

5 = ¾ × a

a = (5 × 4)/ 3 => 20/3

a = 6.67 ms^-2