Question

plz send solution as soon​

Answer 1

For block to be at equilibrium:

• friction will act upwards to balance mg.
• block will experience psuedo force to the left due to acceleration, which will be balanced by Normal.
• Friction = mg
• ma = N

By equating all conditions:

$\implies\rm f_s = mg$

$\implies\rm \mu N = mg$

$\implies\rm 0.2\times N= 2\times 10$

$\implies\bf N = 100$

$\implies\rm N = ma$

$\implies\rm 100 = 2a$

$\implies\bf a = 50\: ms^{-2}$

Instàntaneous power:

$\implies \bf P_{ins} = \vec{F}.\vec{ V}$

•• so,velocity of block at t= 4s

• v = u + at
• v = 0 + (50)(4)
• v = 200 m/s

★ Instàntaneous power by normal force at t = 4s;

$\implies\rm P_{ins} = \vec{F}.\vec{ V}$

$\implies\rm P_{ins} = N\times 200$

$\implies\rm P_{ins} = 100\times 200$

$\implies\bf P_{ins} = 2\times 10^4 \: Joules\: per\: sec$

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