A block of mass 5.0 kg slides down an incline having an inclination of 30^ ^ ^ and a length of 10 m . Determine the work done by the force of gravity.

Correct answer: B. 245 J Mass of the block, m = 5.0 kg Length of the incline, s = 10 m Angle of inclination, θ = 30^ ^ ^ Vertical height moved by the block, h = s θ = 10 30^ ^ ^ = 10 × (1)/(2) = 5 m Work done by the force of gravity is given by W = mgh Taking g = 9.8 m/s^2 , W = 5.0 × 9.8 × 5 = 245 J

Concepts Of Physics MCQ Edition [Volume 1]

Exam: Concepts Of Physics MCQ Edition [Volume 1]
Subject: Physics
Chapter: Work and Energy

Concepts Of Physics MCQ Edition [Volume 1] · Physics · Work and Energy

A block of mass 5.0 kg slides down an incline having an inclination...

A block of mass

5.0 \text{ kg}

slides down an incline having an inclination of

30^{}^{{}^{\circ}}

and a length of

10 \text{ m}

. Determine the work done by the force of gravity.

Options

A $490 \text{ J}$
B $245 \text{ J}$
C $-245 \text{ J}$
D $250 \text{ J}$

Correct answer

B. $245 \text{ J}$

Step-by-step solution

Mass of the block,

m = 5.0 \text{ kg}

Length of the incline,

s = 10 \text{ m}

Angle of inclination,

\theta = 30^{}^{{}^{\circ}}

Vertical height moved by the block,

h = s \sin\theta = 10 \sin 30^{}^{{}^{\circ}} = 10 \times \dfrac{1}{2} = 5 \text{ m}

Work done by the force of gravity is given by

W = mgh

Taking

g = 9.8 \text{ m/s}^2

W = 5.0 \times 9.8 \times 5 = 245 \text{ J}

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