2. Force, Motion & Gravitation Flashcards
what is mass
measure of amount of matter in the object
what is mass measured in
kg
does mass change from earth to space
no
what is the weight of an objec
defined as the force of gravity on the object and may be calculated as the mass times the acceleration of gravity
what is the equation for calculating the weight of a object
w = mg
what is the unit for weight
N
what is gravity
9.8m/s^2
what is the centre of mass
point where all of mass of an object is concentrated
what will happen when the object is supported at its centre of mass
it will remain at static equilibrium
what is newtons first law
law of inertia
object in state of motion or state of rest will remain in that state unless a net force acts on it
what is newtons second law
object is acted upon by a net force, the change in the object state of motion will be inversely proportional to the mass of the object and force acting on the object
what is the formula for newtons second law
F = m x a
what is newtons third law
for every action there is an equal (in size) and opposite (in direction) reaction
what is gravitation
force of attraction existing between any 2 bodies of masses in the universe
what is r in the gravitation equation
measured as distance from centre of one mass to centre of other
what is the gravitation force equation
F = G((m1 x m2)/r^2)
what is G in the gravitation formula
6.673 x 10^-11m^3kg^-1s^-2
___ N is the force needed to accelerate one kg of mass at the rate of one m/s^2
1
what is free fall motion
vertical motion of an object with reference towards earth
what is the kinematic equation for distance (x)
x = x0 + v0t + 1/2at^2
in free fall motion what is a equal to
gravity
what is the kinematic equation for velocity (v)
v = v0 +at
what is the kinematic equation for velocity squared (v^2)
V^2 = v0^2 + 2ax
do linear motion equations apply to projectile motion
no as they follow a parabola in terms of motion
how do you solve projectile motion questions
- separate projectile motion into 2 components - x and y
- calculate linear y component (acceleration = 9.8m/s^2)
- calculate linear horizontal component (no air resistance so horizontal acceleration = 0)
- input values into linear motion equations
what is the equation for maximum friction
fmax = uN
u = coefficient of friction
N = normal force to surface on which object rests
what are the 2 things to remember for friction
a frictional force is always parallel to surface in contact with object
normal force is always perpendicular to the surface in contact with object
what are the 2 forces acting on object in inclined planes
force of gravity downwards (weight)
normal force perpendicular to surface of object
what equation can be used to determine the perpendicular component of gravity in solving problems for objects down an incline
F1 = m x g x cos
what equation can be used to determine the parallel component of gravity in solving problems for objects down an incline
F2 = m x g x sin
what is the acceleration of the object on an incline if there is no friction present
parallel component/mass
A = (m x g x sin)/m
A = g x sin
what is the centripetal acceleration
particle moving in circular motion at constant speed where the constantly changing direction of the velocity is causing radially inward acceleration
what is centripetal acceleration determined by in terms of equations
ac = v^2/r
what is the equation for centripetal force
if ac = v^2/r & Fc = m x ac
then
Fc = mv^2/r
what is hookes law
F = kx
k = spring constant
what is tension
force acting on a flexible object with no mass such as rope or string
if there is no friction on the rope what is assume about tension
that it is equal throughout the rope
