Two objects, x and y, have equal mass and are moving with speeds u and 3u respectively. Their kinetic energies k_x and k_y are related as
[amp_mcq option1=”k_x = k_y” option2=”2k_x = k_y” option3=”9k_x = k_y” option4=”3k_x = k_y” correct=”option3″]
This question was previously asked in
UPSC CAPF – 2022
For object x, mass is m and speed is u, so k_x = ½ mu².
For object y, mass is m and speed is 3u, so k_y = ½ m(3u)² = ½ m(9u²) = 9 (½ mu²).
Comparing k_y with k_x, we find k_y = 9k_x, or 9k_x = k_y.