A 18kg crate is pushed across the floor, using a force that makes an angle of 21o with the horizontal. The coefficient of static friction between crate and floor is s = 0.45. The coefficient of kinetic friction between crate and floor is k = 0.20. Find the strength of pushing force required to just start the crate sliding. Then find the acceleration it will have if it is pushed with the same force once it starts sliding. a) Draw a free body diagram of the crate. For this, assume that it is not sliding, but that the static friction force is at its maximum strength. Leave the magnitude of the push force as a variable. b) Choose an x-y cartesian coordinate system and sketch it on or next to your free body diagram from (a). c) Write out the Newton's Second Law equation for the crate in x and y force components. d) Solve the equations in (c) for the magnitude of pushing force required. e) When the crate starts sliding, you can simply replace the static friction in your part-a through part-c with kinetic friction, and replace the 'not sliding' condition with an unknown acceleration to solve for