Forces and Energy Changes: Resolving Forces

• Forces are vectors and they have both magnitude (size) and direction. • When several forces act upon an object at once, they can be resolved into a single force that has the same effect. This is known as the resultant force. • The vertical and horizontal components of a force can be calculated using simple trigonometry. • If the original force is F, and it is at an angle θ to the horizontal, then: - The horizontal component = F cos(θ) - The vertical component = F sin(θ) • If an object is at equilibrium, the resultant force acting on it is zero. This means the sum of all forces in any direction (up, down, left, right) is equal. • The forces acting up must balance the forces acting down and the forces acting right must balance the forces acting left. • The work done by a force is equal to the force multiplied by the distance it moves in the direction of the force. This is represented by the equation Work done (J) = Force (N) x Distance (m) • Energy cannot be created or destroyed, only transferred from one form to another. This is the principle of conservation of energy. • The energy changes that occur when a force is applied often involve a transformation from one form of energy to another. For example, kinetic energy may be transformed into thermal energy due to friction. • The power of a force can be calculated by dividing the work done by the time taken. This is represented by the equation Power (W) = Work done (J) / Time (s).