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
Newton's Laws of Motion

Concepts Of Physics MCQ Edition [Volume 1] · Physics · Newton's Laws of Motion

A pendulum bob of mass 50 g hangs from the ceiling of an elevator....

A pendulum bob of mass 50 g50 \text{ g} hangs from the ceiling of an elevator. Determine the tension in the string given that the elevator is travelling upward with a deceleration of 1.2 m/s21.2 \text{ m/s}^2.

Options

  1. A0.43 N0.43 \text{ N}
  2. B0.49 N0.49 \text{ N}
  3. C0.44 N0.44 \text{ N}
  4. D0.55 N0.55 \text{ N}

Correct answer

A. 0.43 N0.43 \text{ N}

Step-by-step solution

Mass of the bob, m=50 g=0.05 kgm = 50 \text{ g} = 0.05 \text{ kg}

The elevator is travelling upward with a deceleration of 1.2 m/s21.2 \text{ m/s}^2. This implies the acceleration of the elevator is directed downward, with magnitude a=1.2 m/s2a = 1.2 \text{ m/s}^2.

Writing the equation of motion for the bob:

mg−T=mamg - T = ma

T=m(g−a)T = m(g - a)

Substituting g=9.8 m/s2g = 9.8 \text{ m/s}^2 and a=1.2 m/s2a = 1.2 \text{ m/s}^2:

T=0.05(9.8−1.2)T = 0.05(9.8 - 1.2)

T=0.05×8.6T = 0.05 \times 8.6

T=0.43 NT = 0.43 \text{ N}
Practice Newton's Laws of Motion on Quantrex Academy →

More from Newton's Laws of Motion

A block with a mass of 2 kg rests on a long frictionless horizontal table and is pulled… Concepts Of Physics MCQ Edition [Volume 1]A block of mass 0.2 kg is suspended from the ceiling by a light string. A second block of… Concepts Of Physics MCQ Edition [Volume 1]Placed on a smooth horizontal table, two blocks of equal mass m are connected by a light… Concepts Of Physics MCQ Edition [Volume 1]In a TV picture tube, electrons are emitted from the cathode with negligible speed and… Concepts Of Physics MCQ Edition [Volume 1]Travelling at 40 km/h , a car must be brought to a halt by applying brakes within the… Concepts Of Physics MCQ Edition [Volume 1]A particle of mass 50 g travels along a straight line. The variation of its speed with… Concepts Of Physics MCQ Edition [Volume 1]Two blocks A and B having masses m_A and m_B respectively are placed in contact on a… Concepts Of Physics MCQ Edition [Volume 1]Raindrops, each having a radius of 1 mm and a mass of 4 mg , are falling at a speed of 30… Concepts Of Physics MCQ Edition [Volume 1] Full Newton's Laws of Motion list All Concepts Of Physics MCQ Edition [Volume 1] PYQs