Question

Is it possible to have zero velocity but non-zero acceleration at some instant in a motion? Explain.

Answer 1

yes it is possible
e.g. think of what happens when you throw a ball up in the air - when it reaches its maximum height, its velocity is zero at that instance and its acceleration is g (gravitational acceleration) downwards.

Answer 2

i hope you can explain it to me properly because the last guy did not help at all :(

Answer 3

so you know for the acceleration

Answer 4

it is always there g = 9.8 m/s

Answer 5

yes

Answer 6

for this particular case

Answer 7

I'd like to point out that at the top of a parabola there is no accel, no vel and no displacement. The object is not moving.

Answer 8

yup, it won't move. It stops for an instant when it reaches its maximum height

Answer 9

why do you think it stops?

Answer 10

it stop for an instant doesn't it?

Answer 11

you are right it does stop - but do you know why?

Answer 12

that.. I don't know. I guess it has something to do with acceleration due to gravity? :$

Answer 13

bingo!

Answer 14

yes, but again... in this case... there is no acceleration, so it isn't a solution to your question...

The answer to your question is no.
getting back to F=ma and the fact that velocity = integral of acceleration...

Answer 15

when you throw it up, you it an initial velocity so it starts to climb.
but gravitational acceleration is continuously slowing it down
until eventually its velocity goes from UP to ZERO to DOWN
throughout this motion, it experiences gravitational acceleration downwards

Answer 16

oh. But there is acceleration

Answer 17

it says 'non-zero acceleration' I presume there's acceleration?

Answer 18

I suppose you could cheat and be axiomic, describing light waves relative to other light beams.

Answer 19

Ahhh, i get what you mean. But is it possible to have zero acceleration but non-zero velocity at some instant in a motion>

Answer 20

I was thinking of like a car.. say I'm driving 50 m/s for 10 s, and I decided to push my cruising control button and go at a constant speed of 60 m/s for 25 seconds and slow down after..

Answer 21

'cause zero acceleration = constant speed and idk..

Answer 22

@milliex, yes you can. a moving body with no external force applied to it will continue to move with the same velocity and will therefore have no no acceleration
remember that acceleration is the rate of change of velocity - so if the velocity is not changing, then the acceleration must be zero

Answer 23

so what is an example for that, that perhaps can be relatable to everyday life?

Answer 24

if you drive a car at a constant speed, then its acceleration will be zero.

Answer 25

ohhh, okay! Thank you!!!

Answer 26

A cart moving on a frictionless surface.
You push it to get it going, but then it will have 0 acceleration and continue with constant speed.

The issue with describing "real" things that happen like this is they dont happen like this, because of friction...

Answer 27

@milliex51 - no problem - glad to help