Forces Flashcards
What is a vector?
Has magnitude and direction.
What is a scalar?
A physical quantity that has magnitude.
Examples of scalars
Distance Speed Time Energy Mass
Examples of vectors
Displacement
Velocity
Acceleration
Force
What do forces make an object do?
Start moving Stop moving Change speed Change direction Change shape
What are the contact forces?
Friction
Air resistance
Reaction
Tension
What are the none contact forces?
Gravitational force
Magnetic forces
Electrostatic forces
What is weight?
The weight of an object is the force acting on it due to gravity. Weight is measured in Newtons (N).
What is mass?
The mass of an object depends on the quantity of matter in it. Mass is measured in kilograms (Kg).
What is the equation for weight?
Weight = mass x gravitational field strength
W= m x g
What is terminal velocity?
Terminal velocity is when the object reaches a constant velocity when the frictional force in it is equal and opposite to its weight. The resultant force is then 0 so the acceleration is 0.
What is the resultant force of an object released in fluid?
The weight - frictional force
What is the centre of mass of an object?
The centre of mass of an object is the point at which it’s mass can be thought of as being concentrated.
What two factors affect the stability of an object?
The width of the base of an object
The height of its centre of mass- higher centre of mass = less stable
How do you work out the centre of mass of an irregular shape?
Cut out irregular shape
Put hole in corner
Use clamp stand to suspend it and draw vertical line using plumb line
Repeat hanging the shape from different corners
Where all lines meet is the centre of mass.
What are forces in an interaction pair?
They are equal in size and opposite in direction.