Projectile Motion Flashcards
whats projectile motion?
the flight path an object takes
what affects the flight path?
-height of release
-velocity of release
-angle of release
-mass of object and air resistance
what thing is true for all projectiles?
the acceleration fue to gravity with continuously act on the mass of the object until the object reaches the ground
whats the flight path of a shot?
relatively slow so can ignore air resistance, it follows a parabolic curve.
- the vertical force goes from positive to negative due to gravity
- the horizontal force remains constant if we IGNORE air resistance
how can long jumpers improve their maximum horizontal distance?
optimum angle of release is 45 degrees
- they can also increase their velocity of release through power, speed and strength training and technique
whats the bernoulli principle ?
refers to the changes in fluid pressure due to difference in fluid velocity
-fluid flow arround irregular shaped projectiles creates changes in pressure as the molecules have to travel different distances to pass around it
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- Fluid moving at high velocity causes a drop in pressure
- fluid moving at low velocity causes an increase in pressure
- Fluid moving slower will create higher pressure and fluid moving faster will create lower pressure causing a pressure differential.
how do Aerofoil (wing) shaped objects produce lift?
air travels faster over the top of the wing creating low pressure but air travels slower under the wing creating high pressure causing lift due to a pressure gradient .
how does a race car spoilers shape create a downforce?
air travels slower over the top = high pressure. air travels faster under = low pressure causing a downward force by a pressure gradient.
what is the magnus effect ?
this is the bernouili principle applied to spinning object. Spin is created by applying a force outside its centre of mass.
- spin causes a projectile to move away from its original fligh path
how does magnus effect work ?
the side of the object thats spinning in the direction of the air will result in a high velocity air flow and therefore low pressure causing a pressure differential.
explain topspin
topspin is created by applying a force above the centre of mass.
E.g. by hitting a tennis ball from low to high and ‘brushing’ up thje back of the ball causing forward rotation around the transverse axis.
-topspin causes the ball to move in a downwards direction
- tennis players can therefore hit the ball much harder but still ensure it lands in the court.
- topspin strokes are harder to return because they bounce higher due to a ground reaction force
explain backspin
backspin is created by applying a force bellow the centre of mass.
E.g. hitting a tennis ball from high to low and ‘slicing’ under neath the ball causing backward rotation around the transverse axis
- backspin causes the ball to move in an upward direction and it seems to ‘float’ or ‘hang’ in the air
- slice shots travel and need to be hit at a slow speed to keep them from going out on court
- backspin causes a lower bounce making it harder for the opponent to reach
