1. ## Question

Could someone help me answer this question?

A bicycle and rider moving at 26 km/h have a kinetic energy of 1.5 kJ.
What is the approximate combined mass of the bicycle and rider?

I cant figure it out. I was using the KE = 1/2mv^2 formula
which rearranges to mass = 2KE/V^2 ?

2. ## Re: Question

fuck engineering studies. just fuck it. seriously just fuck it up theass wif a giant epdilso.

true ?

4. ## Re: Question

Originally Posted by pacey0006
Could someone help me answer this question?

A bicycle and rider moving at 26 km/h have a kinetic energy of 1.5 kJ.
What is the approximate combined mass of the bicycle and rider?

I cant figure it out. I was using the KE = 1/2mv^2 formula
which rearranges to mass = 2KE/V^2 ?

you were right, make sure you converted kJ into J and converted km/h into m/s, sub them in and you'll get 57.5

5. ## Re: Question

Originally Posted by pacey0006
Could someone help me answer this question?

A bicycle and rider moving at 26 km/h have a kinetic energy of 1.5 kJ.
What is the approximate combined mass of the bicycle and rider?

I cant figure it out. I was using the KE = 1/2mv^2 formula
which rearranges to mass = 2KE/V^2 ?

1.5x10^3 = 1/2 x m x (26/3.6)^2
Therefore m = 1.5x10^3 / 26
m = 57.5kg

6. ## Re: Question

Originally Posted by Washy_182
1.5x10^3 = 1/2 x m x (26/3.6)^2
Therefore m = 1.5x10^3 / 26
m = 57.5kg
You forgot a few bits
1.5x10^3 = 1/2 x m x (26/3.6)^2
m=(2x1.5x10^3 )/(26/3.6)^2
m=57.5Kg

7. ## Re: Question

Someone got caught out by the good ol' SI unit trick!

Look out tomorrow, its certain to be there once, twice or even three times!

8. ## Re: Question

Originally Posted by BenBrownTown
You forgot a few bits
1.5x10^3 = 1/2 x m x (26/3.6)^2
m=(2x1.5x10^3 )/(26/3.6)^2
m=57.5Kg
Still got the right answer though...

Markers will look at my working and give me full marks, even though I was lazy and skipped a line of working.

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