12. Class 11th Physics | MOD | Solved Example-8 on Uniform Acceleration | by Ashish Arora

# 12. Class 11th Physics | MOD | Solved Example-8 on Uniform Acceleration | by Ashish Arora

In this e.g. we are given that a car and a
truck starts from same point, along same direction. a car with initial speed of two meters-per
second and acceleration two meter-per second-square. And a truck with a constant speed of twenty
meters-per-second. We are required to find the time after which,
car will overtake the, truck. Now in this situation, (again) we first draw
the physical situation. say if this is the car. and this is the truck. we are given that car starts, at an initial
speed of two meters per second. and it is accelerated with an acceleration
of two meters per second square. and the truck continuously moves with a constant speed u-t=
twenty meters per second. So obviously as initially truck is moving
fast compare to car, it will be, moving ahead of the car, but due to acceleration car will
speed up, and at some point of time, the car will be able to overtake the truck. So their will be a time. when, their displacement will again become
equal. so if we find out the displacements, say this
the time t-not, at which again displacement becomes equal. We can find out displacements for truck you
can simply write, as it is moving with uniform velocity, so displacement of truck can be
written as twenty into t-not, that is velocity into time. For car if we find out the displacement to
displacement of car can be written as, initially speed is two acceleration is two, it is u-t,
+ half into a into t square, this we are going to use. now, obviously for over taking. we can write displacement of truck=displacement
of car. so we equate the displacements will get twenty
t-not=two t-not + t-not square, here one t-not get’s cancelled out, directly we get
the value of t-not, as eighteen seconds. this is the answer to this question. so this time t=eighteen second when car will
overtake the(truck).

## 5 Replies to “12. Class 11th Physics | MOD | Solved Example-8 on Uniform Acceleration | by Ashish Arora”

1. Yash Gupta says:

2. that_beautifuldream says:

* not related to the lecture:
* sorry its a bit long, but it wont hurt you if you help me with my life π
sir i have not taken any coaching till half the 12th standard. and recently i got connected to internet and got to see the beautiful lectures so handy.. but my time ran out…….. is it worth if i study home with accordance to your each and every damn video lecture from 11th basics to 12 although my 11 wasn't good in physics. except physical my chemistry organic and inorg is awesome but i wont mind if teachers teach me stuff. Maths is a bit confusing if i am BOSSing NCERT the JEE Mains and Advance look nowhere similar to the problems mentioned, yup i know there are things to be learnt further……. and thats why i'm asking is it worth taking a drop and now just focussing on 12th boards which is like 12 days from now i guess?
Highly great full to teachers for uploading such high quality stuff for us.
You're just building the nation's base strong sir! cant express my gratitude π
Thanku for being there with us!
JAI HIND!

3. Shrijeet Shivdekar says:

sir, i am unable to access the assignment i.e practice questions section of physics galaxy website. please help. that section consists of questions of each lesson divided into about 17 levels. in order to attempt a level, we have to attempt the preceding levels compulsorily. please make that option available as i am thoroughly dependent on it for my advanced preparation

4. Rohit Kumar says:

Can't we use relative velocity ? Because iam getting wrong ans by relative motion

5. Himanshu Pandey says:

SIR CAN WE USE RELATIVE VELOVITY HERE ?????