GATE 2018 ME (ME2) – Question 35
A ball is released from rest at height 1 m inside the frictionless tube shown. Approximating the tube by two straight lines and ignoring the curved portion, find the total distance travelled by the ball (m), to two decimal places.
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Correct answer: MTA
Explanation
The official decision is **marks to all**. Energy conservation makes the first rise on the incline reach the original vertical height of 1 m. Distance to that first turning point is $1+1/\sin45^\circ=2.414$ m. With no friction the ball then reverses and oscillates indefinitely, so unrestricted total distance is unbounded. The stem does not specify stopping at the first turning point.