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21 Cards in this Set
- Front
- Back
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Projectile Motion |
A projectile is an object that is projected into the air and then only gravity exerts a force. ( ignore air resistance) eg. Throwing, kicking, hitting and leaping |
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Projectile Path |
Projectiles follow a parabolic trajectory (path). The ONLY force is gravity acting straight down. Velocity increases vertically and is constant horizontally. |
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Horizontal Formula |
v= s/t |
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Vertical Formulae |
a=v-u/t s = ut + ½ at² v² = u² + 2as
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Vertical and horizontal relationship |
t is the same for both and is called flight time. v, s, u are all different |
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Maximum Range |
Achieved when the angle of release is at 45˚, this is only for complete parabola's however. This optimises both flight time (vertical) and ground speed (horizontal). |
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Range equation |
=Initial Horizontal velocity X time. =UhXt or R = u2sin 2θ/g
*only for the whole parabola example |
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Partial Parabola's |
If the height of release is above the target then the angle must be below 45˚. If the height of release is below the target then the angle must be above 45˚. |
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Circular Motion |
Things will execute a circular path if they continually experience a force at right angles to their direction of motion. |
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Centripetal Force |
Fc, the force towards the centre. The force needed depends on mass, speed, radius.
Fc= mv/r |
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Centripetal Acceleration |
Since F=ma Ac= v²/r = Fc/m |
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Period |
the time to go around once.hehe |
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Useful Relationships |
v= 2πr/t speed= circumference/period
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Vertical Circular Motion |
TOP Fc=T+wt also T=mv²/r - mg MIDDLE Fc=T BOTTOM Fc=T-wt T= mv²/r + mg
Top Take away |
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Critical speed |
When the tension is equal to zero. |
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Loop the Loop example |
TOP Fc=R + wt and R= mv²/r - mg BOTTOM Fc=R - wt and R=mv²/r + mg
*v= √gr |
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Leaning |
Many examples in life where leaning takes place, surfing, skateboarding, running bends, bicycle. |
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Leaning Vectors |
There are two forces on the 'leaner', the weight force and the reaction force, these cause a resultant force known as the centripetal force. Which in this case is provided by friction. |
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Equations of leaning |
tan∆=wt/Fc tan∆= mg/(mv²/r) tan∆=gr/v² |
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Banking |
If a track is banked at the right angle there is no need for friction. eg . race tracks, velodromes. where tan∆=v²/gr |
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Conical Pendulum |
Resolving the vector formed. Tv=mg Th=mv²/r |
