Help with uncertain velocity?

Posted on 2016-05-04 18:48:00 in Physics by ARIANA

An electron is moving at 2.83 x 106 m/s. 
(a) What is the uncertainty in the velocity of the electron if you want to know its location to within 9 mm? 
(b) Assuming a proton is moving at the same speed, what is the uncertainty in its velocity if you want to know its location to within 9 mm? 

For (a) I was told use the equation: 
m(Δv)(Δx)=h Δv= 2.83 x 10^6 

Δx= 9nm 
h= 6.63 x 10^-34 
m=9.11 x 10^-31 
so I set up the equation like this: (9.11x10^-31)(2.83 x 10^6)(9nm)=6.63 x 10^-34 
so in order to figure out what the uncertain velocity is i multiplied (9.11 x 10^-31)(2.83 x 10^6)(9nm) and then divided it by 6.63 x 10^-34 
but it keeps saying the answer is wrong. 
can someone please tell me the proper way to set up the equation? Physics is not my thing and the triangles are super confusing. I will award full points with best answer to whoever can tell me what the right answer is for both a & b. thank you!

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