How Do You Calculate Bicycle Deceleration?

[Masschaos]

1. I need to find the deceleration of a bicycle, I have Finial velocity at 0, initial velocity at 5.56m/s and discplacement at 1.80m



2. V^2+U^2/(2*S)=A
not sure if formula is correct

The Attempt at a Solution

I find that 0^2+5.56^2/(2*180) = -27m/s/s
Is this correct? i think its too fast

 

[Doc Al]

I find that 0^2+5.56^2/(2*180) = -27m/s/s
Is this correct? i think its too fast

Redo your arithmetic.

 

[Masschaos]

(v^2-u^2)/(2*s)=a

(0^2-5.56^2)/(2*1.8m) = -27m/s/s

... is that better?
Is the formula incorrect?

 

[tiny-tim]

Welcome to PF!

Hi Masschaos! Welcome to PF!

(try using the X² tag just above the Reply box )

I find that 0^2+5.56^2/(2*180) = -27m/s/s
Is this correct? i think its too fast

Your formula (a = -u²/2s) is correct, but your arithmetic isn't …

did you multiply by 1.8 instead of dividing?

(you don't seem very good at using brackets)

 

[Masschaos]

Thanks! its late at night here and i was stressing because i thought i had the wrong formula for my assignment... thanks for the heads up

So what i should do is (v²-u²)/2*1.8)?

 

[Doc Al]

So what i should do is (v²-u²)/2*1.8)?

Yes. The formula is a = (v² - u²)/(2*s), not ((v² - u²)/2)*s (which is what you seemed to be doing). I suspect you are just being sloppy with your calculator.