Circular Motion 1
If 5 revolutions take 356 seconds.
Give the PERIOD for one revolution.
The y velocity at a peak height is
0 m/s
Define escape velocity
The speed required for an object to overcome the gravitational pull of a planet.
There is _________ acceleration along the horizontal x axis.
zero acceleration
A planet's orbital period is proportional to the size of its orbit.
a) Kepler's First Law
b) Kepler's Second Law
c) Kepler's Third Law
A planet's orbital period is proportional to the size of its orbit.
Kepler's Second Law
What is the formula for centripetal acceleration
Calculate the RANGE for a cannon which covers a peak height in 6 seconds. The cannon has an initial x velocity of 10 m/s.
s = V x t
s = 10 x 2(6)
s = 120m
The imaginary line joining a planet and the Sun sweeps equal areas of space during equal time intervals as the planet orbits.
Kepler's Second Law
Find the final Y velocity for a cannon as it strikes the ground. Note the initial Y velocity 0 and the time taken to strike the ground from the peak is 3 seconds.
Vy = Uy + at
Vy = Uy + at
Vy = 0 + 9.8(3)
Vy = 29.4 m/s
A skater comes off a ramp at an initial x velocity of 10m/s.
The time taken to reach the peak was 4 seconds.
CALCULATE the RANGE or HORIZONTAL DISPLACEMENT for the skater.
s = 10 x 2(4)
s = 80m
Give the formula for centripetal force.
Fc = mv2 / r
Calculate the initial X and Y velocity for a skater who moves off a ramp at an angle of 30o
The initial velocity of the skater is 15 m/s.
X initial velocity = 15 Cos 30 = 13 m/s
Y initial velocity = 15 Sin 30 = 7.5 m/s
The squares of the orbital periods of the planets are directly proportional to the cubes of the semi-major axes of their orbits.
a) Keplers First Law
b) Keplers Second Law
c) Keplers Third Law
Keplers Third Law
A skater comes off a ramp at an initial x velocity of 11m/s.
The time taken to reach the peak was 2 seconds.
CALCULATE the RANGE or HORIZONTAL DISPLACEMENT for the skater.
s = V x t
s = 11 x 2(2)
s = 44m
An electric bike is moving around a circular track at a speed of 20 km/hr.
The track has a radius of 12m.
CALCULATE the acceleration.
a = v2/r
a = 202/12
a = 0.46 m/s/s
Calculate the CENTRIPETAL FORCE for a washing machine with a radius of 0.5 m.
A 1.2kg bag is placed in the machine and moves at a velocity of 2m/s.
Fc = mv2 / r
Fc = mv2 / r
Fc = (1.2)(2)2 / 0.5
Fc = 9.6 N
A skater comes off a ramp at an initial x velocity of 12m/s.
The time taken to reach the peak was 2 seconds.
CALCULATE the RANGE or HORIZONTAL DISPLACEMENT for the skater.
s = V x t
s = 12 x 2(2)
s = 48m
Which TWO formulas are required to derive the ESCAPE VELOCITY formula.
v = (square root) 2GM/r
Kinetic energy formula
1/2 mv2
Potential energy formula
GMm/r
Find the VELOCITY for a cannon as it hits the ground.
The X velocity is 10 m/s
The Y velocity is 15 m/s
V = square root (102 + 152)
V = square root (325)
V = 18 m/s
Calculate the ANGULAR VELOCITY for a wheel.
The wheel has a radius of 20 m and completes one revolution in 5 seconds.
V = 2 x (pi) x r / T
V = 2 x (3.14) x 20 / 5
V = 25.13 m/s
An electric bike is moving around a circular track at a speed of 40 km/hr.
The track has a radius of 10m.
CALCULATE the acceleration.
a = v2/r
a = v2/r
a = 112/10
a = 12.3 m/s/s
The initial Y velocity was 7.5 m/s.
The final velocity is 0 at the peak.
CALCULATE the TIME TAKEN to reach a peak.
v = u + at
v = u + at
t = v-u/a
t = -7.5 /9.8
t = 0.77 seconds
R3 /T2 = R3 /T2
Use the formula to find the PERIOD for PLANET B
20003km / 0.52 Earth days = 30003 km/T2
T = (square root) 30003 (0.5)2 / 20003
T = 5.13 x 10^-3
If the average time to fall from a ride is 5 seconds. Calculate height of the ride.
s= ut +1/2at2
s= ut +1/2at2
s= 0 + 4.9 x 52
s= 122.5 m
The initial Y velocity was 15 m/s.
The final velocity is 0 at the peak.
CALCULATE the TIME TAKEN to reach a peak.
v = u + at
v = u + at
t = v-u/a
t = -15 /9.8
t = 1.53 seconds