If a particle is in equilibrium is the initial speed always 0?

I get that there's no acceleration if the particle is in equilibrium and that the particle is either stationary or moving at a constant velocity.

Am I wrong in saying neither of those prove the initial speed must be 0?

Essentially the question I'm referring to the particle is originally in equilibrium before a force is removed. I've worked out the acceleration, am given that t=3, and I'm meant to find out the distance travelled by the particle, so of course I need either the initial speed, final velocity. The answer says u=0 which prompted me to ask this question.

I get that there's no acceleration if the particle is in equilibrium and that the particle is either stationary or moving at a constant velocity.

Am I wrong in saying neither of those prove the initial speed must be 0?

Essentially the question I'm referring to the particle is originally in equilibrium before a force is removed. I've worked out the acceleration, am given that t=3, and I'm meant to find out the distance travelled by the particle, so of course I need either the initial speed, final velocity. The answer says u=0 which prompted me to ask this question.

You are exactly right. Can be constant velocity or at rest. Hard to give a sure answer here for this specific question. Check the wording to look for any hints

Please post the full question.

Think the answer I was looking for was in fact in the question, it asks to find the distance travelled during the first 3 seconds of motion, so we know that u=0. Correct me if I'm wrong

I would normally understand "equilibrium" to mean that the particle is in the same place for all time, so necessarily velocity and acceleration are zero.

Can you please post the question in full i.e. post the exact wording that you're seeing in e.g. your textbook.

So you're saying that for you, non-zero constant speed would not mean that a particle was in equilibrium? Or am I misunderstanding you?

Yes, that's how I'd usually use the term. I guess in line with

https://en.wikipedia.org/wiki/Equilibrium_point

but I can imagine the word may get used in different ways.

Yes, that's how I'd usually use the term. I guess in line with

https://en.wikipedia.org/wiki/Equilibrium_point

but I can imagine the word may get used in different ways.

PS now reading the given question, it doesn't matter whether the particle is in motion or not.

Surely it does? At initial speed of 1 million ms^-1 and acceleration of whatever, the particle will come cover a much longer distance in 3 seconds than at initial speed of 0.

The question says to give the distance after the first 3 seconds of motion. That means we assume it was stationary when in equilibrium right, and so we know from that u must be 0.

Im not 100% sure but if a particle is in equilibrium isnt it traveling at 10x the speed of light? (3x10>4 km>-1s^-1) ?

I would assume that it was at rest, as ‘first three seconds of motion’ implies that at t=0 it was not moving, and beginning motion.

This agrees with the Edexcel (well at least the Edexcel M1 textbook) definition:



although I can't find this definition anywhere else outside of A Level which is a bit odd.

I'm pretty sure that an exam question would never be ambiguous and just say equilibrium if the body is at rest - normally questions say "rests in equilibrium".