Machine-translated by Google. Questions are authored in English.
Top

Discussion

What is the minimum velocity with which a body of mass m must enter a vertical loop of radius R at the bottom so that it can complete the loop?

  • A.√(2gR)
  • B.√(3gR)
  • C.√(gR)
  • D.√(5gR)

Answer: D

The minimum entry speed is \(\sqrt{5gR}\).

At the top of the loop, gravity must at least supply the centripetal force: \[mg = \frac{mv_{top}^2}{R} \Rightarrow v_{top}^2 = gR\]

Applying conservation of energy between bottom and top, a height \(2R\) apart: \[\tfrac{1}{2}mv^2 = \tfrac{1}{2}mv_{top}^2 + mg(2R)\]

\[v^2 = gR + 4gR = 5gR \Rightarrow v = \sqrt{5gR}\]

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.