How can F = mg sin. θ be proven on a smooth plane?

[DarkNess_wtc]

i can't understand the formula

F = mg sin. θ

on a smooth plane

how to proof a = g sin. θ

sin. θ...




http://img213.imageshack.us/img213/2313/44877072.jpg

 

[Doc Al]

Do you understand how to find the components of a vector using trig functions of a right triangle?

You might want to read this: http://www.physicsclassroom.com/Class/vectors/u3l3e.cfm"

Ask yourself:
What forces act on the object? What are their components parallel and perpendicular to the incline? What's the net force on the object? Then apply Newton's 2nd law.

 

[DarkNess_wtc]

oic...

thanks for your ans