Forces Flashcards
Define ‘resultant force’
The sum of all the individual forces acting on an object (taking directions into account)
What happens if a resultant force acts on
an object?
It causes a change of momentum in the direction of the force
How can a resultant force change the motion of an object?
It can change speed and direction
How can the resultant force be found
Adding force vectors together, tip (arrow)
to tail.
What happens if there is zero resultant
force
the object will remain stationary, or (if
moving) will continue to move in the
same direction with the same speed
Define friction
Friction is the force providing resistance to the motion of two surfaces sliding past each other
Give an example of a frictional force
air resistance
When work is done overcoming friction, what occurs?
Energy is dissipated resulting in heating
When does circular motion occur?
When a force is acting perpendicular to the force of an object
Describe the speed and velocity of an object in circular motion
- speed is constant
- The velocity is always changing, since it is constantly changing direction
Give an example of a force causing circular motion
Gravity, which causes the earth to orbit the sun
State Hooke’s law
The force on an object is directly proportional to its extension
Give the equation for Hooke’s Law
F= kx
At what point does Hooke’s Law no longer apply
The limit of proportionality
What does the limit of proportionality look like on an extension-load graph
Where the graph stops being linear
