+1 vote
in JEE by (2.4k points)
edited by

A 11.7 ft wide ditch with the approach roads at an angle of 15° with the horizontal. With what minimum speed should a motorbike be moving on the road so that it safely crosses the ditch?


1 Answer

+2 votes
by (9.9k points)
selected by
Best answer

The center of mass of motor bike is C and it is in the shown position just before it is supposed to have taken off.  C' is the position when the bike lands safely ie., the rear part B must land on the road on the other side.

CC' is the range for the flight of the bike.  CC' = R
                   = 11.7' + 2.5' cos 15° + 2.5' Cos 15° = 16.53'

We assume that the angle of projection of center of mass is 15°.

Range for a two dimensional projectile : R = u² Sin 2Ф / g  = u² Sin (2*15°) / g
          u = √(2 R g ) = √(2*16.53 * 9.8 / 0.3048) = 32.6 feet / sec

We do not consider some other factors like rotation about center of mass, friction etc. while answering this question.

by (2.4k points)
Oh Thanks .....

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.