physics question

Question

A 16.3kg box is accelerating down a 35° incline. What is the normal force on the box? Give your answer . . .
in terms of Newtons. Do not include units in your answer. They will be assumed to be N.
to a precision of tenths of a N. Use a format like ##.# or #.# in your answer.
to an accuracy of 0.2 N. Answers within 0.2 N of the correct answer will be tolerated.

 

Written by the book^. Any help would be great!!!!

Answer 1

Angle of incline is theta = 35 deg, mass m = 16.3 kg, g = 9.8m/s^2

let x-axis be along the incline and y-axis is perpendicular to it. 

A normal force N acts along y-axis. And gravitational force mg acts vertically downwards. 

sum over Forces along y axis is : N - mg cos theta = 0 

So N = mg cos theta = 16.3* 9.8 cos (35) = 130.8 N