A 45kg block slides down an incline that is angled at 41 degrees. If the coefficient of kinetic friction between the block and the incline is 0.45 what is the block's acceleration?

Answer 1

normal component of weight = 45*9.81* cos 41
so friction force = 0.45* 45*9.81*cos 41

component of weight down slope = 45*9.81 * sin 41

so
45 a = 45*9.81*sin 41 - .45*45*9.81*cos 41
or
a = 9.81* (sin 41 - .45 cos 41)

Answer 2

The distance from the earth to the sun is 1.5 times 10 to the 11 power m ( 93 million miles) and the time it takes for one complete orbit of the earth about the sun is one year. How long would it take for a planet located at twice this distance from the sun to complete one orbit?