Question

4 kg block at rest on a smooth horizontal surface upper surface of 4 kg is a rough a block of mass 2 kg is placed on its upper surface the acceleration of upper Block with respect to earth when the 4 kg mass is pulled by a force of 30 newton is

Answer 1

Answer:

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Answer 2

Given:

4 kg block at rest on a smooth horizontal surface, upper surface of 4 kg is a rough. A block of mass 2 kg is placed on its upper surface. The acceleration of upper Block with respect to earth when the 4 kg mass is pulled by a force of 30 newton, is

To Find:

Acceleration of a 2kg block with respect to earth?

Solution:

Acceleration of system is

$=\dfrac{30}{4+2}\\ =5 m/s^{2}$.

Now, Force applied on 2kg block= 2×5= 10N

Static friction on 2kg block= 0.8×2×10

= 16N                         ( $\[{\mu _s} = 0.8\]$  is given in the figure.)

Since, here

static friction > applied force.

So, upper block will move along with the system and no slipping will take place on upper surface.

Therefore,  acceleration of 2kg block with respect to earth = 5m/s^2