Question

NO. 19. In the above situation, minimum force needed to move the block is N. (g=10 m/s2) 5kg u=0.5 1) 20.4 N 2) 2214N 3) 25.4 N 4) 25 N​

Answer 1

Gɪᴠᴇɴ :-

Mass of the block is m = 5kg

Coefficient of friction μ = 0.5

Acceleration due to gravity g= 10 m/s²

Tᴏ Fɪɴᴅ :-

Minimum force needed to move the block.

Sᴏʟᴜᴛɪᴏɴ :-

As we know that, Limititing Friction is the force which is needed to just move the block.

So, the minimum force is Limititing friction. (fl)

We know that,

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \boxed{ \underline{ \pmb{f_ l = \mu \: _ s \: N}}}$

where,

fl = Limititing friction

μ= coefficient of friction

N = normal reaction

Here, Normal reaction is "mg" (mass× acceleration due to gravity)

Substituting the values,

$\: \: \: \: \: \: \: \: \: \: \: \: \: \implies{ \pmb{f_ l = 0.5 \times \: 5 \times 10}}$

$\: \: \: \: \: \: \: \: \: \: \: \: \: \implies{ \pmb{f_ l = 0.5 \times \: 10 \times 5}}$

$\: \: \: \: \: \: \: \: \: \: \: \: \: \implies{ \pmb{f_ l = 5 \times 5}}$

$\: \: \: \: \: \: \: \: \: \: \: \: \: \implies{ \pmb{f_ l = 25N}}$

So, the minimum force required to move the block is 25N

Correct-option:- 4

Answer 2

From the question, the correct option is 4.

In the given situation, the minimum force needed to move the block is 25N.

As we know that,

Given:

g = 10 m/s²

m = 5kg

u = 0.5

Find out:

The minimum force needed to move the block.

Let us:

Limiting Friction is needed to move the block.

So,

fl = 0.5×5×10

  = 0.5×10×5

  = 5×5

  = 25N ( minimum force needed to move the block )