Question

Closed

Answer 1

is the answer 74m?

Answer 2

wow,yes :o
how lol :/

Answer 3

well, first of all, don't straight away apply the s = ut + 1/2 at^2 formula.
break the sum into 2 parts: first the distance travelled in +x direction and the distance travelled in -x direction. for this, u need to know the instant where velocity becomes 0.
so use eq, v = u + at
0 = 10 - 2t
2t = 10
t = 5sec
so at the 5th sec, velocity in +x direction became 0.

Answer 4

now find the distance travelled in this time. that will give u the first part of the sum.

Answer 5

for the second part, u have initial velocity u = 0
a = -2m/s^2
time t = 12 - 5 = 7sec
so calculate the distance s using these quantities. then add the two distances to get the final answer.

Answer 6

@vaidehi09,when the velocity becomes 0 it would come to rest?
when acceleration acts opposite to velocity,it will slow down and ultimately come to rest?
so what is the 2nd part of question about :|
try a diagram :o

Answer 7

Also,why didn't we use the formula directly?

Answer 8

We can't apply the formula directly because it's for displacement not for distance, and who said to you that when velocity becomes zero and acceleration is there particle slows down. Throw a particle up in the air, at the highest point v=0 and a is non zero and after that speed increases.

Answer 9

so what actually happens when velocity and acceleration are opposite?

Answer 10

As the particle comes to rest first and then moves inthe same direction of acceleration.

Answer 11

Means finally both v and a have the same direction

Answer 12

ohkay! thanks for clearing,acceleration has that much power :o

Answer 13

Adding question to your question. Try to find displacement.

Answer 14

-24 m?

Answer 15

@DLS yup, that's the displacement.

Answer 16

okay!

Answer 17

Yes, its the displacement which is -24m and the distance travelled is 74m.

Answer 18

Thanks a lot guys! :)

Answer 19

@DLS do u understand why the displacement is negative? and what it actually means [w.r.t the motion on the particle] ?

Answer 20

yes,it went to the opposite direction due to opposite acceleration?

Answer 21

good! that's correct.

Answer 22

Closing this now!Thanks :)