P-5 Forces Flashcards
- What is a vector quantity
- Have magnitude and associated direction
- Force is a vector quantity
What is a scalar quantity
- Only have magnitude no direction
- Speed, distance
How are vectors represented
- Represented usually by an arrow
- length of arrow represents magnitude and direction shows direction
What are contact forces
- Objects are touching for the force to act
- friction, air resistance, tension and normal contact
What are non-contact forces
- Objects that do not need too be touching for force to act
- e.g magnetic, gravitational and electrostatic
What is a force
- A push or pull that acts on an object due to the interaction with another object
- Vector
What happens when objects interact
- There is a force produced on both objects
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What is an interaction pair
- Paire of forces that are equal and opposite and act in two interacting objects
What is weight
- The force acting on an object due to gravitational field around earth
What does weight depends on
- Gravitational field strength
What is the equation for weight
Weight = Mass x gravitational field strength
W = m g
weight in newtons
Directly proportional
What are the two effects of gravity
- Makes all things fall towards ground
- Gives things weight
- What is a centre of mass
- When the weight of an object is considering to act at a single point
- A point where the whole mass is concentrated
How is weight measured
- Using a calibrated spring balance
- A newtonmeter
What is a resultant force
- ## When a number of forces are acting on an object are replaced by a ginned force that has the same effect as all the force as all the other forces acting together
How do you calculate the resultant forces that act in a straight line
- Add the forces that go in the same direction and subtract that which go in the other direction
What are free body diagrams
- Sizes of arrows show relative magnitudes
- Directions are those which re true
What is work done
- When a force causes an object to move through a distance work is done
- Force does work on an object when the force causes a displacement of the object
- What is the equation for work done
- Work done = force time distance
Work done- joules
Force- newtons
- Distance meters
W= F s
What is a joule of work done
- When of force of one newton causes displacment of one meter
- 1 joule = 1 newton meter
- What energy is transferred in one work done
- Energy transfers from one store to another
e. g- electric to kinetic
What effect does work done have affect frictional forces
- Frictional forces acting on an object when met with work done cause the temperature to rise