Question

a body travelling in straight line travels 2m in the first 2 seconds and 2.2m in the next four second with constant retardation. What will be its velocity at the end of seventh second from the start

Answer 1

plzzanswer

Answer 2

Let me solve it myself please)

Answer 3

kk

Answer 4

Formula for motion with constant acceleration is in one dimension, which is the case
s = s0+v0t+at^2/2
You can definitely find what you need using it

Answer 5

Try to solve it yourself

Answer 6

elaborate

Answer 7

Ask me what you don't understand in how to use it.

Answer 8

i understood nothin

Answer 9

Ok. It's better for you in future to read about kinematics.
So what is given is
t1 = 2 s, s1 = 2 m
t2 = 6 s, s2 = 4.2 m
s0 = 0 because we arranged our system of coordinates so that initial position of an object at the origin of it.
a - which is acceleration, is constant, so we can use equations of kinematics for motion with constant acceleration. Do you get that?

Answer 10

Is that clear, what I wrote?

Answer 11

Hey man are you here?;)

Answer 12

i got it but i don't know kinematics

Answer 13

Ok, it doesn't matter. Now our equation becomes
s = v0t+at^2/2
using values of s1 and t1 you can express v0 in term of a.

Answer 14

yes

Answer 15

You can type in your current data so we can check if it is right.

Answer 16

v0 - ?

Answer 17

1

Answer 18

No) try again

Answer 19

-1

Answer 20

Ok I'll show you the steps

Answer 21

s1 = 2m, t1 =2s
2 = v0 *2 + a 2^2/2
1 = v0 + a
v0 = 1 - a

Answer 22

and our equation becomes more "simple"
s = (1-a)t + at^2/2

Answer 23

it should be 1-2a i think?

Answer 24

Ok let's try again
2 = v0 *2 + a 2^2/2
2 = v0 *2 + a *4/2
2 = v0 *2 + a *2
1 = v0 + a
v0 = 1 - a
Do you have any doubts about this now?

Answer 25

no

Answer 26

I am going on:
and our equation becomes more "simple"
s = (1-a)t + at^2/2

Answer 27

yeah iam gettin it now

Answer 28

Putting in s and t values you can find a.
When you will find a, using another equation of kinematics for motion with constant acceleration, you can easily find v for any moment of time
v = v0 + at

Answer 29

Notice that you will get negative value for acceleration because its retardation, if it's not negative, be sure you got wrong value.

Answer 30

i know these equation
v=u+at
s=ut+1/2at^2
v^2-U^2=2as
are these equation of kinematics

Answer 31

I'm not sure about the last one because it takes time to derive it, yes these are equations of kinematics for motion with constant acceleration.

Answer 32

Here U is initial velocity!

Answer 33

i know