Question

Two blocks of masses 2 kg. and 1 kg. are in contact with each other on a frictionless table . When a horizontal force of 3 N is applied to the block of mass 2 kg. the value of the force of contact between the two block is :
(1) 4 N (2) 3N (3) 5 N (4) 1 N...
please justify

Answer 1

Answer:

The value of force contact between two blocks is 1N. Option D is the right answer.

Explanation:

The blocks in contact with respective masses has an applied force horizontally over one mass so the contact force between them is calculated as following -

Given: Mass of one block m1 = 2 kg

Mass of other block m2 = 1 kg

Force applied F = 3 N

Therefore, the force applied on the mass will cause the motion in the block system, which is given by –

Force = mass x acceleration

Force on block system = mass of block system x acceleration of system

3 = ( 2 + 1 ) x a

a = 3 / 3

$\mathrm{a}=1 \mathrm{m} / \mathrm{s}^{2}$

Now if the acceleration of the block system is 1 m / s 2 then the force exerted on mass m1 will be  

Force on mass m1 = m1 x acceleration of m2

Force on m1 = 2 x 1

Force on m1 = 2 N

Similarly, Force on m2 = m2 x acceleration

Force on m2 = 1 x 1

Force on m2 = 1 N

Therefore, the contact force between them = Force on m1 – Force on m2  

Contact force = 2 – 1

Contact Force = 1 N

Answer 2

Answer:1N

Explanation:

a=F÷3

a=3÷3=1

a=1

t1=m2 ×a

  =1×1=1

t1=1N