All Exams Test series for 1 year @ ₹349 only
Question

A body of mass m is dropped from a height h. When it has fallen through a distance of 2h/3, the ratio of its kinetic energy to potential energy is __________.

This question was previously asked in
RRB JE 2025 CBT 2 Mechanical and Allied Engg Question Paper English (2-Jul-2026) (Shift-1)
The correct answer is

2:1

To solve this problem, we need to determine the ratio of kinetic energy to potential energy of a body when it has fallen through a distance of \frac{2h}{3} after being dropped from a height h.

1. **Initial Conditions**:

  • The body is initially at rest at height h with total potential energy and no kinetic energy.
  • Initial Potential Energy (PEinitial) = mgh, where m is the mass and g is the acceleration due to gravity.

2. **When the body has fallen through \frac{2h}{3}**:

  • The new height is \frac{h}{3} (since the body has descended \frac{2h}{3}).
  • Potential Energy at this point (PEnew) = mg \times \frac{h}{3} = \frac{mgh}{3}.

3. **Calculating the Kinetic Energy**:

  • By the conservation of energy, the total mechanical energy at any point is equal to the initial potential energy.
  • Total mechanical energy = Initial Potential Energy = mgh.
  • Kinetic Energy (KE) when the body has fallen = Total mechanical energy - New Potential Energy.
  • Kinetic Energy = mgh - \frac{mgh}{3} = \frac{2mgh}{3}.

4. **Determining the Ratio**:

  • The ratio of Kinetic Energy to Potential Energy at \frac{2h}{3} height is:
  • \frac{KE}{PE} = \frac{\frac{2mgh}{3}}{\frac{mgh}{3}} = \frac{2}{1}.

Thus, the ratio of the kinetic energy to potential energy when the body has fallen through a distance of \frac{2h}{3} is 2:1.

Was this answer helpful?

Similar Questions

  1. A particle of mass m starts from rest and moves with constant acceleration 'a'. After travelling a distance 's', what is its kinetic energy? 


Important Questions from Work Power and Energy

  1. Which of the following is an example of potential energy?

  2. Energy in natural systems is transferred by _______.

    Choose the best option from the following.

  3. _______ is one of the chemical used to produce Ocean Thermal Energy.

  4. A body of mass 2kg is thrown up vertically with a kinetic energy of 500J. If the acceleration due to gravity is 10 m/s2, the height at which the kinetic energy of the body becomes half of the original values is _____

  5. Arjun has a mass of 50 kg, he eats banana of 1000 calories. If this energy is used up to lift him from the ground, the height to which he can climb is _______. Take g = 10 m/s2 and  1 calories = 4.2 Joule.

Need Expert Advice?
Test Series
RRB JE img
Railways
RRB JE (CBT 1 + CBT 2) 2026 Mock Test Series
1210 Tests 7 Tests Free
English, Hindi

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App