## anonymous 4 years ago An armoured vehicle of mass 5000kg is at rest on a frozen lake where friction is practically zero. It fires a shell of mass 10kg with a nuzzle velocity of 800m/s [N]. Let the time take to travel the length of the barrel be "B" seconds. Calculate the acceleration of the shell

1. anonymous

Well, if we assume that the shell accelerates uniformly as it travels through the barrel, we can use $v_f^2 = v_i^2 + 2a\Delta x$ since v_i = 0, we can solve for a: $a = \frac{v_f^2}{2\Delta x}$ where delta x is the length of the barrel.

2. anonymous

so my answer could have the variable x in it and it would still be right

3. anonymous

Oh, I'm sorry I misread the question. I should have used the other equation:

4. anonymous

Actually it's not even an equation, it's a definition: $a = \frac{\Delta v}{t} = \frac{v_f}{B}$

5. anonymous

i got an answer of $800m/s/B$

6. anonymous

does it not give you the time B?

7. anonymous

btw how do you do fractions on this thing and no it doesnt

8. anonymous

Odd. And the syntax is \frac{ numerator }{ denominator }

9. anonymous

inside the $braces of course. 10. anonymous alright thanks. so i guess \[\frac{800m/s}{B}$

11. anonymous

Yep

12. anonymous

thanks

13. anonymous

No problem