1. Tardigrade
  2. Question
  3. Physics
  4. An object is allowed to fall from a height R above the earth, where R is the radius of earth. Its velocity when it strikes the earth's surface, ignoring air resistance, will be

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. An object is allowed to fall from a height $R$ above the earth, where $R$ is the radius of earth. Its velocity when it strikes the earth's surface, ignoring air resistance, will be

JEE MainJEE Main 2023Motion in a Straight Line

Solution:

Loss in PE = Gain in KE
$ \left(-\frac{ GMm }{2 R }\right)-\left(-\frac{ GMm }{ R }\right)=\frac{1}{2} mv ^2 $
$ \Rightarrow v ^2=\frac{ GM }{ R }= gR$
$ \Rightarrow v =\sqrt{ gR }$