[JennM]

Hello,
I'm having a heck of a time with this problem and I was hoping someone could tell me what I was doing wrong!

I need to calculate kinetic energy (in J) of an electron whose speed is 75 km/hr.  I know the formula is 1/2*m*u^2.  The mass of an electron is 9.10938188 * 10^-31 kg and I believe the unit needs to be in m^2 s^2.  I found a conversion for km/hr to m/s which is 3.60, but I'm still not coming up to the book's answer of 2.0 * 10^-28 J.

Any suggestions?! 
Thanks!

[enahs]

You converted from km/hr to m/s wrong.

75 km * 1000m    *  1hr        *    1min
   1hr       1km           60min           60sec


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