The condition of apparent weightlessness can be created momentarily when a plane flies over the top of a vertical circle. At a speed of 900 km h⁻¹, the radius of the vertical circle that the pilot must use is ______ km.
Physics · Mixed Chapter
JEE Main Practice

Question

The condition of apparent weightlessness can be created momentarily when a plane flies over the top of a vertical circle. At a speed of 900 km h⁻¹, the radius of the vertical circle that the pilot must use is ______ km.

Physics · Mixed Chapter

G1 Physics · Accepted Answer

Step 1: At top of the circle, apparent weightlessness corresponds to normal reaction N = 0. Step 2: Thus mg = mv²/r ⇒ r = v²/g. Step 3: Convert v = 900 km h⁻¹ = 900 × 5/18 = 250 m s⁻¹. Step 4: r = 250²/9.8 = 6377.55 m = 6.37755 km. Final answer ≈ 6.4 km.