Three forces Weight (mg), Normal reaction, R and Friction ,T act on a particle on an inclined plane. The resultant of these three forces is shown as the vector in orange. Adjust the three forces so that the system is in equilibrium. When you have produced a situation of equilibrium, compare the ratio of T/R with tan (the angle of the slope).
Downloadable Files
If your computer is set up with Geometers Sketchpad 4 then you can download this file to investigate forces along a slope problems further.
Software/Applets used on this page

Uses Cinderella interactive geometry
Glossary
equilibrium
the state of an object when the vector sum of all forces acting on it is zero and when the algebraic sum of the moments of the forces about any point is zero
friction
whenever two rough surfaces are in contact, this force, F acts in the direction to oppose motion.
normal reaction
Gravity exerts a downward force on you and the Earth exerts this upward force on you to balance the force of gravity, usually denoted by R.
particle
an object with negligible size and internal structure, which can be represented by a point; the fundamental assumption in mechanics.
slope
the angle between a straight line and the horizontal.
vector
A mathematical object with magnitude and direction.
weight
a force which acts upon masses in a gravitational field. Near the surface of the Earth, the acceleration due to gravity is approximately constant; this means that an object's weight is roughly proportional to its mass. Weight and mass are fundamentally different quantities: mass is an intrinsic property of matter, whereas weight is a force that results from the action of gravity on matter: it measures how strongly gravity pulls on that matter.
This question appears in the following syllabi:
Syllabus | Module | Section | Topic | Exam Year |
---|---|---|---|---|
AQA A-Level (UK - Pre-2017) | M1 | Statics | Forces as vectors | - |
AQA A2 Maths 2017 | Mechanics | Equilibrium and Resolving | Resolving Forces | - |
AQA AS/A2 Maths 2017 | Mechanics | Equilibrium and Resolving | Resolving Forces | - |
CCEA A-Level (NI) | M1 | Statics | Forces as vectors | - |
CIE A-Level (UK) | M1 | Statics | Forces as vectors | - |
Edexcel A-Level (UK - Pre-2017) | M1 | Statics | Forces as vectors | - |
Edexcel A2 Maths 2017 | Mechanics | Resolving Forces and Friction | Resolving Forces | - |
Edexcel AS/A2 Maths 2017 | Mechanics | Resolving Forces and Friction | Resolving Forces | - |
OCR A-Level (UK - Pre-2017) | M1 | Statics | Forces as vectors | - |
OCR A2 Maths 2017 | Mechanics | Resolving Forces and Equilibrium | Resolving Forces | - |
OCR MEI A2 Maths 2017 | Mechanics | Resolving Forces and Equilibrium | Resolving Forces | - |
OCR-MEI A-Level (UK - Pre-2017) | M1 | Statics | Forces as vectors | - |
Pre-U A-Level (UK) | Mech | Statics | Forces as vectors | - |
Universal (all site questions) | S | Statics | Forces as vectors | - |
WJEC A-Level (Wales) | M1 | Statics | Forces as vectors | - |