LEVERS
What are the three parts of a lever? (whiteboard)
Axis (fulcrum/pivot), force (effort) and resistance (load).
What are the two external forces acting on a projectile? (whiteboard)
Gravity and air resistance.
What is stability? (whiteboard)
The ability to resist a change in equilibrium.
Which law is known as the law of inertia? (whiteboard)
Newtons First Law
What is the equation for momentum? (whiteboard)
Momentum = mass × velocity
In which class of lever is the force in the middle? (whiteboard)
3rd Class Lever
What angle of release is often ideal for maximum distance? (whiteboard)
45 Degrees
Name one factor that increases stability (whiteboard)
Any one of: larger base of support, lower centre of gravity, line of gravity within the base of support, greater mass or greater friction.
State Newton’s Second Law equation. (whiteboard)
Force = Mass x Acceleration
What is inertia? (whiteboard)
Inertia is the resistance of a body to changing its state of motion.
What is the difference between the force arm and resistance arm? (whiteboard)
Force arm = distance between force and axis; resistance arm = distance between resistance and axis.
How does increasing the height of release affect distance, if other factors stay the same? (whiteboard)
It generally increases the distance travelled.
Explain why standing with your feet further apart increases stability. (whiteboard)
A wider stance creates a larger base of support, making it harder to disrupt equilibrium.
Explain why a heavier medicine ball accelerates less than a netball when the same force is applied. (whiteboard)
A medicine ball has greater mass, so the same force produces less acceleration.
A 4 kg ball travels at 3 m/s. Calculate its momentum. (whiteboard)
Momentum = 12kg·m/s
A baseball player holds the bat further up to shorten the lever. Explain one advantage and one disadvantage. (whiteboard)
Advantage: shorter lever is easier to control and swing. Disadvantage: lower swing velocity and potentially less hitting distance.
Why might a tennis shot use a lower angle of release than a volleyball dig? (paper)
A tennis shot often needs a flatter trajectory to travel over the net, while a volleyball dig may require a higher trajectory to gain height.
Explain how lowering your centre of gravity helps you resist being pushed over. (whiteboard)
A lower centre of gravity generally increases stability and makes it harder to tip the athlete over.
A player jumps by pushing down against the ground. Explain this using Newton’s Third Law. (paper)
The player pushes down on the ground (action); the ground pushes upwards on the player with an equal and opposite force (reaction).
Explain how a netball player uses impulse to reduce the force when catching a fast pass (paper)
The player moves their hands backwards or “gives” with the ball, increasing the time over which it is stopped and reducing the impact force.
Explain how increasing the resistance arm can increase swing speed but make the bat harder to swing. (paper)
A longer resistance arm can increase speed and range of motion at the end of the lever, but requires more force to swing because the lever is harder to move.
Explain how a volleyball jump serve can benefit from increased height of release and a changed angle of release. (paper)
Jumping increases the height of release, which can increase flight distance. Changing the angle can create a more effective trajectory; the best angle depends on the desired outcome.
A rugby player prepares to resist a tackle. Explain how they can use three stability factors to maintain balance. (paper)
Any three explained factors: widen the stance, lower the centre of gravity, keep the line of gravity within the base of support, increase friction with the ground, or position the base of support towards the oncoming force.
A football is stationary until kicked, then slows down and stops. Explain the movement using Newton’s First Law and identify the external forces involved. (paper)
First Law: the ball remains at rest until an external force acts on it and would keep moving at constant velocity without an external force. After the kick, friction and air resistance slow it, while gravity acts on it during flight.
Explain how a cricketer uses summation of momentum to generate maximum speed when hitting the ball (paper)
The cricketer coordinates body parts in sequence, beginning with larger and stronger body parts and transferring momentum through the body towards the arms and bat. Good timing, coordination, a stable base and follow-through help maximise the bat’s speed.