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

we know that for calculating the acceleration of upper block formula is


a = F ÷ (M1 + M2)

because there are two masses

a = 30 Newton ÷ (2kg + 4kg)

which gives a = 5 ms^2

Answer 2

Given:

Mass of the block = 4kg

Upper Surface = 4kg

Mass of block placed above = 2kg

Force = 30N

To Find:

Acceleration of the block

Solution:

Acceleration = f = ma

where m is the total mass.

Thus, total mass -

Mass of lower block + Mass of Upper block

= 4 + 2

= 6

Substituting in f = ma

30 = 6a

a = 30/6

a = 5

Answer: The acceleration of the block is 5m/s²