Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
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 2.0 kg is pushed down an inclined plane of...

A block of mass 2.0 kg2.0 \text{ kg} is pushed down an inclined plane of inclination 37^{}^{{}^{\circ}} by a 20 N20 \text{ N} force acting parallel to the incline. It is observed that the block travels on the incline with an acceleration of 10 m/s210 \text{ m/s}^2. Assuming the block starts from rest, determine the work done by the weight of the block during the first second. Take g=10 m/s2g = 10 \text{ m/s}^2.

Options

  1. A100 J100 \text{ J}
  2. B−60 J-60 \text{ J}
  3. C60 J60 \text{ J}
  4. D80 J80 \text{ J}

Correct answer

C. 60 J60 \text{ J}

Step-by-step solution

The distance traveled by the block in the first second is given by the kinematic equation:

s=ut+12at2s = ut + \dfrac{1}{2}at^2

Since the block starts from rest, u=0u = 0. Substituting the given values a=10 m/s2a = 10 \text{ m/s}^2 and t=1 st = 1 \text{ s}:

s=0+12(10)(1)2=5 ms = 0 + \dfrac{1}{2}(10)(1)^2 = 5 \text{ m}

The weight of the block acts vertically downwards, and its component parallel to the inclined plane is mgsin⁡θmg \sin \theta. The work done by the weight of the block is the product of this parallel component and the displacement along the incline:

W=(mgsin⁡θ)×sW = (mg \sin \theta) \times s

Substituting m=2.0 kgm = 2.0 \text{ kg}, g=10 m/s2g = 10 \text{ m/s}^2, \theta = 37^{}^{{}^{\circ}}, and s=5 ms = 5 \text{ m}:

W = (2.0 \times 10 \times \sin 37^{}^{{}^{\circ}}) \times 5

Using \sin 37^{}^{{}^{\circ}} = \dfrac{3}{5}:

W=20×35×5=60 JW = 20 \times \dfrac{3}{5} \times 5 = 60 \text{ J}
Practice Work and Energy on Quantrex Academy →

More from Work and Energy

A block of mass 2.00 kg travelling at a speed of 10.0 m/s accelerates at 3.00 m/s² for… Concepts Of Physics MCQ Edition [Volume 1]A box is pushed a distance of 4.0 m across a floor which offers a resistance of 100 N .… Concepts Of Physics MCQ Edition [Volume 1]The combined mass of a cyclist and the bike is 90 kg . Determine the increase in kinetic… Concepts Of Physics MCQ Edition [Volume 1]A block of mass 5.0 kg slides down an incline having an inclination of 30^ ^ ^ ∘ and a… Concepts Of Physics MCQ Edition [Volume 1]A stationary particle of mass 15 g is accelerated by a constant force of 2.50 N over a… Concepts Of Physics MCQ Edition [Volume 1]A particle travels from a position r _1 = (2 m) i + (3 m) j to a new position r _2 = (3… Concepts Of Physics MCQ Edition [Volume 1]A man travels along a straight horizontal road carrying a block of mass 2 kg in his hand.… Concepts Of Physics MCQ Edition [Volume 1]A particle is acted upon by a force F = a + bx in the x -direction, where a and b are… Concepts Of Physics MCQ Edition [Volume 1] Full Work and Energy list All Concepts Of Physics MCQ Edition [Volume 1] PYQs