# physics

• October 18th 2007, 02:03 PM
jenjen
physics
Hi,

I am trying to help my brother do this problem but I can't figure it out! can anyone please help me...

A 3.45 kg object is moving in a plane, with its x and y coordinates given by x = 7t² - 3 and y = 4t³ + 3, where x and y are in meters and t is in seconds. Find the magnitude of the net force acting on this object at t = 2.35 s.
• October 18th 2007, 02:31 PM
topsquark
Quote:

Originally Posted by jenjen
Hi,

I am trying to help my brother do this problem but I can't figure it out! can anyone please help me...

A 3.45 kg object is moving in a plane, with its x and y coordinates given by x = 7t² - 3 and y = 4t³ + 3, where x and y are in meters and t is in seconds. Find the magnitude of the net force acting on this object at t = 2.35 s.

$\sum \bold{F} = m \bold{a} = m \frac{d^2\bold{x}}{dt^2}$

So the x component of the force would be:
$F_x = m(14)$

and the y component would be...?

-Dan