Posted by **srikala** on Saturday, May 26, 2012 at 5:43am.

A particle moving with a constant acceleration describes in the last second of it's motion 9/25th of the whole distance.of it starts from rest ,how long is the particle is in motion and through what distance does it move if it describes 6cm in first second?

options

1. 5s,150 cm

2. 10s,150 cm

- physics -
**ajayb**, Saturday, May 26, 2012 at 9:01am
Assume the particle's acceleration is a cm/sec^2 and that it moves a distance of S(t)cms in total time of t secs. Also it covers S(t-1) cms. in (t-1) secs.

Since it covers 6cm in the first second => 6 = 0.1 + (1/2).a.1^2 => a=12cm/sec^2.

Now, S(t)-S(t-1)= (1/2).a.[t^2-(t-1)^2]......(1)

Also, S(t)-S(t-1)= (9/25).S(t)= (9/25).(1/2).a.t^2 .....(2)

From the above two equations, you will get the following eqn.

9t^2-50t+25 = 0

Solve it to get two values for t i.e. t=5,10/18 (ignore the second as t is not less than 1sec)

Thus t=5sec and hence S(t)=150cm

Therefore,option (1) is correct.

=

## Answer This Question

## Related Questions

- physics - A particle moving with a constant acceleration describes in the last ...
- physics - 1.Give examples of a one-dimensional motion where (a) the particle ...
- Calculus-particle motion - 1. A particle is moving on the x-axis (or any number ...
- physics - Two particles A and B are in uniform circular motion about a common ...
- Physics (Oscillation) - If a particle moves in simple harmonic motion with a ...
- Maths - a particle starts from rest at o and moves in a straight line so that t ...
- Physics - A 10kg particle undergoes simple harmonic motion with an amplitude of ...
- Physics: Simple Harmonic Motion - A 10kg particle undergoes simple harmonic ...
- physics - A 10 g particle undergoes Simple Harmonic Motion with an amplitude of ...
- Physics HELP - 1.If a particle moves in a plane so that its position is ...

More Related Questions