Question

A box weighing 60N slides down from the top of an inclined plane making an angle of 300 with the horizontal if the body slides 4m along the plane, calculate the work done by the force of gravity.

Answer 1

Given

• Weight of the box = 60 N
• Angle made by the inclined plane = 30°
• Displacement = 4 m

To Find

• Work done

Solution

☯ Work = Fs cos θ

• Where F is the force applied, s is the displacement & θ is the angle made by the inclined plane

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✭ According to the Question :

→ Work = Fs cos θ

→ Work = 60 × 4 × cos(30°)

• cos(30°) = √3/2

→ Work = 60 × 4 × (√3/2)

→ Work = 240 × √3/2

→ Work = 120 × √3

→ Work = 120√3 J

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Or we may also use √3 = 1.73

→ Work = 120 × 1.73

→ Work = 207.6 J

∴ The work done on the box is 207.6

Answer 2

Answer:

Given :-

• Weight of box = 60 N
• Angle = 30⁰
• Distance slide = 4 m

To Find :-

Work done

Solution :-

We know that

$\bf \: W = Fs cos\theta$

Where

F = Force applied

S = Displacement

Cos∅ = Angle made

Since,

The force applied is on the box. So,

We have

F = 60 N

S = 4

Cos∅ = 30

$\sf \implies \: 60 \times 4 \times \cos({30}^{ \circ} )$

$\sf \implies \: 240 \times \cos( {30}^{ \circ} )$

We know that

cos30⁰ = √3/2

$\sf \implies \: 240 \times \dfrac{ \sqrt{3} }{2}$

$\sf \implies \: 120 \times \sqrt{3}$

$\sf \implies120 \sqrt{3}$

So,

• Work done is 120√3 Joules