WAEC - Further Mathematics (2021 - No. 15)
A body of mass 15kg is placed on a smooth plane which is inclined at 60° to the horizontal. If the box is at rest,
calculate the normal reaction to the plane. [ Take g = 10m/s\(^2\) ]
129.9N
75N
60.0N
7.5N
คำอธิบาย
Let the normal reaction be R
R = Wcosø = mgcosø
= 15 * 10cos 60°
= 150 * 0.5000
= 75N