Thread: speed of car

wondering if anyone can help me ...i need answers for A and B...thanks

Originally Posted by carlasader

wondering if anyone can help me ...i need answers for A and B...thanks

For a)

$\displaystyle v = u + at $
$\displaystyle v = 10 + (3)(6) $
$\displaystyle v = 10 + 18 $
$\displaystyle v = 28 \ m.s^{-1} $


For b)

From O to A

$\displaystyle v^2 = u^2 + 2as $
$\displaystyle 100 = 0 + 2(4)(s) $
$\displaystyle s = 12,5 \ metres $

From A to B

$\displaystyle s = ut + \frac{1}{2} at $
$\displaystyle s = (10)(6) + \frac{1}{2} (3)(6) $
$\displaystyle s = 60 + \frac{1}{2} (18) $
$\displaystyle s = 69 $

Add those two answers together to get OB...
Thus OB = 12,5 + 69 = 71,5 metres

Originally Posted by janvdl

...
From A to B

$\displaystyle s = ut + \frac{1}{2} at $
$\displaystyle s = (10)(6) + \frac{1}{2} (3)(6) $
$\displaystyle s = 60 + \frac{1}{2} (18) $
$\displaystyle s = 69 $

Add those two answers together to get OB...
Thus OB = 12,5 + 69 = 71,5 metres

Hello,

you have a small but very effective typo in your calculations:

From A to B

$\displaystyle s = ut + \frac{1}{2} at^2 $
$\displaystyle s = (10)(6) + \frac{1}{2} (3)(36) $
$\displaystyle s = 60 + \frac{1}{2} (108) $
$\displaystyle s = 114 $

Add those two answers together to get OB...
Thus OB = 12,5 + 114= 126.5 metres