Many
a student find free fall equations tough, but the students at STEPS (A program
run by TCY
in Ludhiana, Ambala, Jammu, Karnal and Kurukshetra for NTSE and NSEJS
aspirants) just solve the toughest of free fall problems mentally. I would like
to share their secret with you.

The
first basic principle is the time taken for a change in velocity under uniform
acceleration is given by, “change in velocity/acceleration”

The
second principle is that when you throw a ball up with a velocity of say 20
m/s, then it returns back with a velocity -20 m/s. So the change in velocity is
40 m/s in the direction of acceleration. To simplify things the change in
velocity is simply double the initial velocity.

Using
these two principles let us try to calculate time of flight of a ball thrown up
with a speed of 25 m/s.

Change
in velocity =50 m/s

Acceleration
= 10 m/s

^{2}
Time
= 5 s

Now
isn’t that easy!

Get
Practice questions for every section and mock tests @ http://www.tcyonline.com/exam-preparation-ntse-olympiad-preparation-and-practice-test/100194/ntse-nsejs-kvpy