forces Flashcards
what is a force?
force is a physical quantity that has both magnitude and direction (vector)
can mass be affected by force
no
effects of forces
-change the motion of objects
-start moving a stationary object
-change the speed of a moving object
-change the direction of a moving object
-change the shape/size of an object
what is the SI unit of force
N (newtons)
how can we measure force
spring balance
what are the forces classified into (the 2 types)
contact and non contact forces
list the contact forces
-normal contact force
-friction
-tension
list the non-contact forces
-gravitational force
-magnetic force
- electric force
what is normal contact force
it is a push exerted by a surface on an object pressing on it
what is friction
it is a force that opposes or tends to oppose motion between surfaces in contact
what is tension
the pull exerted by an inextensible string or rope on an object attached to it.
it is always acting in the direction away from the body and along the cord
what is gravitational force
the pull exerted by the earth’s gravity on any object
it acts through the centre of gravity of an object and always acts vertically downwards (aka weight)
what is magnetic force
the attractive(pull) or repulsive(push) forces between magnets
what is electric force
the attractive(pull) repulsive(push) forces between electric charges
when does air resistance increase
-fall at higher speed
-increase surface area
-density of air increases
