Question

a block of mass 4 kg lies over a horizontal surface g=10 m/S2 now another block of mass 2kg placed over 4 kg block find normal reaction between two blocks​

Answer 1

Answer:

Correct option is

A

3

20

The free body diagram of both the blocks are as shown in the figure.

a=

4+2

F

=

4+2

20

=

3

10

Using ΣF

x

=ma

x

For 4kg block, 20−N=4a=4×

3

10

N=20−

3

40

=

3

20

N

This can also be solved as below

For 2kg block, N=2a=2×

3

10

=

3

20

N

Here, N is normal reaction between the

Answer 2

There are two blocks, one of 4 kg and another of 2 kg.

The 2 kg block is placed over the 4 kg block.

• Now when there is only a 4 kg block, The block exerts a force of 40 N on the ground. The ground, in turn, exerts an equal and opposite reaction force of 40 N which acts as normal on the block.

• Now when the 2 kg block is placed on the 4 kg block, the 2 kg block exerts a force of 20 N on the 4 kg block, The 4 kg block, in turn, exerts an equal and opposite reaction force of 20 N on the 2 kg block which acts as normal.