Mechanics 2 Flashcards
Is the period of the simple pendulum directly proportional to its length? explain
no, T² α l
measuring g from a pendulum graph x axis
T²
measuring g from a pendulum graph y axis
length
measuring g from a pendulum graph g
4 π² x slope
How is a pendulum set up so that it swings freely
one end of a string is tied to the pendulum bob and the other fixed end is passed through a split cork attached to a retort stand. pull the bob a little to one side and allow it to swing. keep the angle of the swing small
state isaac Newton’s law of universal gravitation
any two point masses in the universe attract each other with a force that is directly proportional to the product of the masses and inversely proportional to the square if the distance between them
equation for Isaac Newton’s law of universal gravitation
F = GMm/R²
acceleration due to gravity at the surface of the earth
g
forces which cause the earth to spin
gravitational attraction = centripetal force
period of communication of a satellite
24 hours
describe how the centre of gravity of the meter stick is found
balance the meter stick on a suitable fulcrum eg. a wedge. not and record the position on the meter stick that balances the stick horizontally ie. position of equilibrium
Hook’s law
for an object stretched or compressed, the restoring force is directly proportional to the displacement F = -ks
3 examples of SHM
stretched elastic
swinging pendulum through a small angle
vibrating tuning fork
number of oscillations per minute
frequency. 1/T
describe how to get data to verify Boyle’s law
diagram (pressure gauge, scale to read volume, syringe)
get volume by reading scale
pressure by reading gauge
change by moving piston in or out
graph of boyles law x axis
1/V
graph of boyles law y axis
Pressure
verifying boyles law, how to keep temperature constant
after adjusting the piston allow a few minutes to pass before the new values of pressure and volume, to keep at room temperature
what provides the centripetal force to keep the earth moving around the sun
the gravitational force (pull) of the sun on the earth
centripetal force
f = mv² / r
angular velocity
θ/t
centripetal force
the force acting towards the centre of a circle for an object undergoing circular motion
why does the frequency of the received radio signal change as the satellite orbits the sun
this is an example of the doppler effect, as it travels towards the earth a higher frequency is observed and as it travels away from the earth a lower frequency is observed
why is an inextensible string used in a pendulum
so that the length remains constant
accuracy for pendulum
keep the angle of the swing small
velocity
rate of change of momentum
derive ω x r = v
θ = s/r and ω = θ/t
ω = (s/r)/t = s/(r x t)
v = s/t -> ω = v/r
ω x r = v
T =
2π /ω
define pressure
force per unit area
is pressure scalar or vector and explain
scalar as it acts in all directions
state Boyle’s law
for a fixed mass of gas at a constant temperature the pressure of a gas is inversely proportional to the volume of a gas
if the volume is 3 times smaller what is the pressure
3 times bigger
pressure =
ρgh
why does the sphere obeying Hooke’s law oscillate with simple harmonic motion
a = (-ks)/m
a α -s, condition for simple harmonic motion
explain why after an orbit a satellite will be above a different point on the earth’s surface
its period of rotation may not be the same as that of the earth
describe the movement of a sphere on a spring pulled down and explain
it will undergo simple harmonic motion, the acceleration is proportional to the displacement
distance between earth and other planet
measured from centre of each planet!!!
how to find acceleration due to gravity at a distance away from the earth (gs)
divide gs (written in formula) by g (GM/r² )
when is an astronaut actually weightless
when gravity due to earth is equal to gravity due to other planet or moon
why is there no atmosphere on the moon
the gravitational force is too weak to sustain an atmosphere
moment of a force
force x perpendicular distance from axis to line of action of force
formula for f and ω
F = ω/2π
minimum force of a vibrating object occurs when
maximum displacement
maximum force of a vibrating object occurs when
minimum displacement
measure the length of a string in a pendulum
string + radius of bob
how to measure diameter of a bob
vernier callipers
how to find periodic time
measure time for several oscillations, divide by the number of oscillations
