RRB Group D 1 Dec 2025 Shift 2 Solved Paper

Concept:Kinetic energy is directly proportional to the square of velocity. Doubling velocity increases kinetic energy by a factor of 4.Explanation:The formula for kinetic energy is $\mathrm{KE} = \frac{1}{2} m v^2$, where $m$ is mass and $v$ is velocity.When the velocity is doubled, the new velocity is $2v$.Substitute into the formula: new kinetic energy $\mathrm{KE}' = \frac{1}{2} m (2v)^2$.Simplify: $(2v)^2 = 4v^2$, so $\mathrm{KE}' = \frac{1}{2} m \times 4v^2 = 4 \times \left( \frac{1}{2} m v^2 \right) = 4 \times \mathrm{KE}$.Thus, kinetic energy becomes four times the original value.Answer:Four times the original value.