Question

Two objects A and B of mass 2 kg and 3 kg. 3 kg, respectively, were dropped from different heights. A took 5 second and B took 3 seconds to touch the ground. What is the ratio of their kinetic energy with which they hit the ground?

• A. 10/9
• B. 2/3
• C. 50/27
• D. 5/3

Answer 1

Answer:

C. 50/27

Physics - Energy: Kinetic Energy Ratio Calculation

Understanding the Concepts

• Kinetic Energy (KE): The energy possessed by an object due to its motion. It is calculated using the formula: KE = 1/2 * m * v^2, where 'm' is mass and 'v' is velocity.

• Free Fall: When an object falls under the influence of gravity alone, neglecting air resistance.

• Equations of Motion: In uniformly accelerated motion (like free fall), the velocity (v) after time (t) can be found using: v = u + at, where 'u' is initial velocity and 'a' is acceleration. In free fall, initial velocity (u) is usually 0, and acceleration (a) is the acceleration due to gravity (g). So, v = gt.

• It's crucial to remember that in free fall, the acceleration due to gravity (g) is constant for both objects (approximately 9.8 m/s^2), and it cancels out in ratio calculations.

• Pay close attention to the units and the correct application of formulas