Forces and their effect Flashcards
Contact forces
sometimes objects need to be touching for a force to act - the normal contact force that acts between all touching objects
-friction between the cars tyre and the road
Non - contact forces
they are usually caused by interacting fields
-the gravitational attraction between objects like earth and the sun is caused by their gravitational fields interacting
What do interacting fields cause?
what about the electrostatic forces?
they cause attraction or repulsion between magnetic objects and the electrostatic forces causing attraction or repulsion between electric charges is due to interactions between their electric fields.
What kind of force do you show using vector diagrams?
interaction pair - when two objects interact, both objects feel an equal but opposite force
what is a free body diagram?
what do the size of the arrows represent?
shows an object and all its forces acting on it
they show the relative magnitudes of the forces and the directions show the directions of the forces
what does it mean if an objects is in equilibrium?
it has a resultant force of 0
they are either stationary or moving at a steady speed
resultant forces acting on a van- 1200N left
1000N right
the frictional force acting on the van is smaller than the driving force, so there is a resultant force in the horizontal direction = 1200-1000= 200N
how to draw a vector diagram?
always make a scale of maybe 1cm= 1N
draw the first force then from the end point of this line draw the second force
join the start and end up and this is the net force and use a protractor to find the angle of start to find bearing
vector quantity and examples
have a force and a direction - displacement, velocity, weight
scalar quantity and examples
only have a magnitude and no direction - distance, speed, mass
