ok ive been wondering about this for a while. 0 / 0 ??
what is the answer?
when you take the equation of motion - v = u + at
and rearrange it to: t = (v-u)/a
if you are travelling at a constant velocity then a = 0 and v-u = 0
so you get: t = 0/0.
so what would time be in this case?
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- Thread Starter
- 22-01-2010 18:36
- PS Helper
- 22-01-2010 18:43
if you are travelling at constant velocity, then the final velocity = intial velocity irrespectve of the duration of motion. therefore, t doesnt have a solution
- 22-01-2010 20:29
There would be no need to solve for t in this case. The only place you'd need to find t is if the car was travelling at a constant speed v over a displacement s.
(Original post by Devp93)
- 22-01-2010 23:08
t = (v-u)/a
In this circumstance, if you take a look at what you've written down you'll quickly realise that the physical meaning is this:
How long does it take me to get from initial velocity, u, to final velocity, v, assuming I am accelerating with acceleration, a?
Evidently, the answer is that it takes no time at all, i.e. the answer is zero.
So what does this mean mathematically? It means that the numerator is "more zero" (strange concept I know) than the denominator. This is a concept that you will consider more deeply when you do more pure mathematics - the idea that some infinite functions will reach a limit "faster" than other functions which reach the same limit. In the situation you've described, the mathematical understanding is that the fact that the final velocity is the same as the initial velocity, overrides the fact that it takes zero time to get from one speed to the otherLast edited by Chwirkytheappleboy; 22-01-2010 at 23:11.
- Thread Starter
- 23-01-2010 00:35
cool that helps a lot thanks