The Vector Nature of Newton's Second Law

1. Dec 14, 2004

thomasrules

A block of mass 2.0kg is placed on a smooth plane, inclined to the horizontal at an angle of 15degrees. The force of gravity, acting straight down on the block, is 20N.
a) What is the acceleration of the block down the plane?

I'm having trouble with this because I know:
Net F=fgcostheta-friction
or fgcostheta-friction=ma=2a

BUT THERE IS NO FRICTION GIVEN NOR A COEFFICIENT OF FRICTION

THanks

Last edited: Dec 14, 2004
2. Dec 14, 2004

Nylex

Of course you don't have a coefficient of friction. A smooth plane implies no friction! Also, the component of the weight acting parallel to the plane is mgsin theta.

Last edited: Dec 14, 2004
3. Dec 14, 2004

thomasrules

Ya I'm a real dumbass I also made a 2 other dumb mistakes......i used fgcostheta instead of fgsintheta....THANKS ANYWAY !!!!! grrrrrrrrrrrrrrrrrrrr