Question

A car of mass 850 kg rests on a slope at 25 to the horizontal. Calculate the magnitude of the component of the cars weight which acts parallel to the slope

Answer 1

Answer:

Gravity always points straight down with a magnitude of mg, however since the car is sitting on a slope you can break gravity up into two easier components, the one parallel to the slope and the one perpendicular to the slope. In this manner you form a triangle making up the components of mg and using basic trig find the other components

Example:

50 kg on a 45o slope

mg = 50 kg * 9.8 m/s = 490 kgm/s2 (hypotenuse of triangle)

the component parallel to the slope (x) can be found with:

sin( 45o ) = x / 490 => x = 490 * sin( 45o) = 346.48 kg*m/s2

Edit: Just realized my choice of slope may be confusing but you want to find the angle between the perpendicular component and the hypotenuse, in your case this would be 90 - 25 = 65, and use that for your angle in the trig portion