Projectile MotionProjectile Motion

What is projectile?What is projectile?

A projectile is any object released into the A projectile is any object released into the air. Once an object is in the air its flight air. Once an object is in the air its flight path is governed by factors prior to its path is governed by factors prior to its release.release.

Factors affecting the Factors affecting the flight path of a Projectile flight path of a Projectile are:are:

GravityGravity Air ResistanceAir Resistance Speed of ReleaseSpeed of Release Angle of ReleaseAngle of Release Height of ReleaseHeight of Release SpinSpin

Speed of Release Speed of Release

This refers to This refers to how fast how fast the object is the object is released (thrown or hit).released (thrown or hit).

A projectiles speed of release is largely A projectiles speed of release is largely determined by the muscle force.determined by the muscle force.

Generally, the Generally, the greatergreater the the speed of speed of releaserelease, the , the greatergreater the the distance gaineddistance gained

Angle of ReleaseAngle of Release

This refers to the angle that the object is This refers to the angle that the object is thrown at or hit into the airthrown at or hit into the air

Angle of ReleaseAngle of Release

In sporting situations the angle of release In sporting situations the angle of release varies according to the activity. In varies according to the activity. In activities such as shooting a basketball activities such as shooting a basketball angle above 45 degrees is required. In angle above 45 degrees is required. In activities such as tennis a lower, around -activities such as tennis a lower, around -3 to 15 degree angle is required.3 to 15 degree angle is required.

Angle of ReleaseAngle of Release

What would happen if the angle of release were too What would happen if the angle of release were too high for a given activity?high for a given activity?

Poor distance gainedPoor distance gained

What would happen if the angle of release were too What would happen if the angle of release were too low for a given activity?low for a given activity?

Poor flight time and possibly poor distancePoor flight time and possibly poor distance

Height of ReleaseHeight of Release

This refers to how high above the This refers to how high above the ground an object is released at. ground an object is released at.

Height of ReleaseHeight of Release

Increasing the height of release improves Increasing the height of release improves the horizontal distance objects can be the horizontal distance objects can be projected.projected.

For a given speed and angle of release, For a given speed and angle of release, the greater the height of release the the greater the height of release the greater the distance gained.greater the distance gained.

This is because the time in the air will be This is because the time in the air will be greater.greater.

Height of ReleaseHeight of Release

Would this mean that a golfer hitting a Would this mean that a golfer hitting a ball off the top of a hill would hit it further ball off the top of a hill would hit it further than a golfer at the bottom of the hill? than a golfer at the bottom of the hill? Why?Why?

Yes – the ball will stay in the air longer so Yes – the ball will stay in the air longer so will have a greater chance to fly further. will have a greater chance to fly further. This assumes the same club and force is This assumes the same club and force is used.used.

SpinSpin When applying force to a projectile below, When applying force to a projectile below,

above or to the side of the COG you will above or to the side of the COG you will impart spin onto the projectile.impart spin onto the projectile.

This helps the projectile to maintain its This helps the projectile to maintain its course and can cause it to change height course and can cause it to change height or direction.or direction.

SpinSpin

Spin happens as a ball moving through Spin happens as a ball moving through the air will move in the direction of least the air will move in the direction of least air pressure. air pressure.

When you hit the ball you create an area When you hit the ball you create an area of high pressure meaning the ball will of high pressure meaning the ball will travel in the opposite direction to the side travel in the opposite direction to the side you hit.you hit.

Spin continued…Spin continued…There are 4 main types of spin that can be imparted to a projectile:

1.Top Spin – this is where you hit over the ball.

Top spin creates a downward force on the ball causing the ball to drop.

Spin continued…Spin continued…

2. Back Spin – this is where you hit under or slice the ball.

Backspin creates an upward force that lifts the ball causing the ball to rise.

Spin continued . . .Spin continued . . .

3. Clockwise Spin 3. Clockwise Spin – this is where you hit – this is where you hit the ball on the left side of the COG. the ball on the left side of the COG.

It causes the ball to swing to the Right.It causes the ball to swing to the Right.

Spin continued . . .Spin continued . . .

4. Anticlockwise Spin 4. Anticlockwise Spin – this is where you – this is where you hit the ball on the rightside of the COG. hit the ball on the rightside of the COG.

It causes the ball to swing to the Left.It causes the ball to swing to the Left.

GravityGravity

What is the effect of gravity on a What is the effect of gravity on a projectile?projectile?

It decreases the height a projectile can It decreases the height a projectile can attain.attain.

Air ResistanceAir Resistance

There are several key factors that bring air There are several key factors that bring air resistance into play:resistance into play:

The larger the surface area, the more air resistance The larger the surface area, the more air resistance will affect the object. E.g a basketball compared to will affect the object. E.g a basketball compared to a golf ball.a golf ball.

The type of surface of the object. If the surface is The type of surface of the object. If the surface is rough then air resistance will be greater.rough then air resistance will be greater.

Speed. As speed increases, so does air resistance. Speed. As speed increases, so does air resistance. E.g a space shuttle (friction)E.g a space shuttle (friction)

Mass. The smaller the mass (lighter the object), the Mass. The smaller the mass (lighter the object), the more air resistance will affect it.more air resistance will affect it.