P8 - Forces In Balance Flashcards
(52 cards)
What is the difference between scalar and vector quantities?
Scalar quantities have magnitude only, vector quantities have magnitude and direction
How can a vector quantity be represented?
An arrow
What is a force?
A push or pull that acts on an object due to the interaction with another object
What are contact forces and give 4 examples?
- Objects are physically touching
- Friction, air resistance, tension, normal
What are non contact forces, give 3 examples?
- Objects are physically separated
- Gravitational, electrostatic, magnetic
What is weight?
A force acting on an object due to gravity
What type of quantity is force?
Vector
What causes the force of gravity close to Earth?
Gravitational field around the Earth
What does the weight of an object depend on?
The gravitation field strength at the point where the object is at
What is the equation that links gravitational field strength, mass and weight?
weight(N)=mass(kg)* gravitational field strength (N/kg)
What happens when the resultant force is 0?
- Forces are balanced meaning movement will not change(direction can’t change)
What is the centre of mass?
Point at which weight of an object acts through
What is the relationship between the weight and mass of an object?
The weight of an object and the mass of an object are directly proportional
What is the resultant force?
A single force that is the result of all different forces acting on the object
What happens when there is a resultant force?
Speed or shape or direction changes
Describe examples of the forces acting on an isolated object or system
- Gravitational force(like in planets)
- Electromagnetic force(as in magnets)
- Nuclear force(within atomic nucleus)
What is an isolated object?
- A system which isn’t influened by other external systems but experiences internal forces
What are free body diagrams used for?
Used to describe situations where several forces act on the object
What can a single force be resolved into?
- Two components acting at right angles to each other
- Have the same effect as the single force
When is work done on an object?
When a force causes displacement of an object
What is the equation that links distance, force and work done?
work done(J) = force(N)* distance(m)
How many NM(newton metres) is 1 Joule?
1 newton-metre
What causes a rise in the temperature of an object?
Work done against the frictional forces acting on an object
Illustrate resolution of forces, equilibrium situations and determine the resultant of two forces to include both magnitude and direction
- Skydiver’s weight acts on him pulling him towards the ground
- Drag (air resistsance) acts on him too, opposite to his motion
- Sizes of arrows show magnitudes of forces and directions show direction of forces