Chapter 4 Laws of Motion Flashcards
forces can be _____?
summed
is force a vector?
yes
inertia
the tendency of an object to resist a change to its current state of motion/velocity (think potato and knife)
what has more inertia?
massive objects; mass is directly related to inertia
newton’s first law of motion (law of inertia)
an object at rest (or moving at constant velocity) will remain at rest (or moving at. constant velocity) unless acted on bye a external force
newton’s second of motion
the net force acting one an objects directly proportional to its mass and its acceleration. Fnet=ma; Fnet= sum of all forces
what can we conclude about acceleration from newtons first law?
if an object accelerates, according to newton’s first law, there must be a force applied to it
what is the relationship between force and acceleration?
they are directly proportional; if the force is doubled on an object then the acceleration doubles as well (mass constant)
what is the relationship between mass and acceleration?
mass and acceleration are indirectly proportional; if the mass of an object then the object’s acceleration will be half of its original value (force constant)
dimensional analysis of the second law for SI unit of force
Fnet= [ma]= [m][a]= ML/T^2
SI unit of force
1 N= 1 kg*m/s^2
weight
the force due to gravity acting on an object near a much more massive object
the weight of an object of mass (m). has a magnitude given by ____
Fg=mg
newtons third law of motion (action equals reaction)
whenever a body exerts a force on a second body, the first body experiences a force that is equal in magnitude and opposite in direction (F12 = -F21)
the normal force is always ____?
perpendicular to a surface
what happens if there is no surface?
then there is no normal force
