Topic 9 Forces and their effects Flashcards
What is a force?
A force is a push or pull on an object that can cause it to accelerate, decelerate, change direction, or change shape. It is measured in newtons (N).
What are contact forces?
Contact forces are forces that occur when objects are physically touching, such as friction, air resistance, tension, and normal contact force.
What are non-contact forces?
Non-contact forces act at a distance without physical contact, such as gravitational force, electrostatic force, and magnetic force.
What is the resultant force?
The resultant force is the overall force acting on an object when all individual forces are combined. It determines the object’s acceleration or deceleration.
How do you calculate resultant force?
Resultant force = Sum of all forces in one direction - Sum of all forces in the opposite direction.
What is inertia?
Inertia is the tendency of an object to resist changes in its motion. An object with more mass has greater inertia.
What is friction?
Friction is a contact force that opposes the relative motion between two surfaces. It can slow down or stop moving objects.
What is air resistance?
Air resistance is a type of frictional force that acts against an object’s motion through the air, increasing with speed and surface area.
What is terminal velocity?
Terminal velocity is the constant speed that a falling object reaches when the force of air resistance equals the gravitational force, resulting in zero acceleration.
What is the moment of a force?
The moment of a force is the turning effect of the force around a pivot point. It is calculated using the equation:
Equation: Moment = Force × Perpendicular distance from the pivot
Units: Newton-meters (N·m)
What is the principle of moments?
For an object in equilibrium, the sum of clockwise moments equals the sum of anticlockwise moments.
How can levers and gears be used to transmit rotational forces?
Levers increase the distance over which a force acts, making it easier to lift heavy objects. Gears change the direction and magnitude of forces, allowing for speed or force adjustments.
