forces
What is a force?
A force is a push/ pull placed upon an object that changes its momentum.
Which Newton's law is the law of inertia?
Newton's first law.
How many types of levers are there?
45 degrees.
list some factors that can affect stability
- size of the base support
- location of the centre of gravity
- line of gravity
- body mass
What is the acceleration of gravity on Earth?
It is 9.8m/s.
Give an example of Newton's first law in soccer.
The foot of a soccer player changes the motion of a soccer ball (when it is at rest- creating motion or in motion- stopping it to rest)
What are the three parts of a lever?
pivot, load, effort
Is greater impulse a good thing?
Yes, it allows for more time to create force or disperse force.
How could you change your centre of gravity?
raise arms above head- raise COG, move arms to right- shift COG to right
What are 3 different drag forces?
Friction, air resistance and drag force
What is the equation for momentum?
Momentum=Mass x Velocity
Give an example of a third class lever in the body.
arm (hitting something), leg (kicking something)
Why is summation of forces important in batting in cricket?
Stepping forward, bringing body back and then moving forwards again and swinging the bat forward, following through to create greater power.
Why is the Fosbury flop better than other methods of high jump?
The centre of gravity was outside the body and below the bar, allowing the person to jump higher.
How could you increase friction?
chalk for grip in gymnastics, waxing the board for surfing
What is an example of Newton's 3rd Law in Volleyball?
The ball hits the net which causes the net to rebound and the ball to bounce off it.
Give an example of a first class lever in the body
The head (spine=effort), head= load
Give a detailed example of the summation of forces involved in taking a basketball shot.
bending ankles- bending knees- bending waist- bending shoulder- bending elbow- bending wrist
all of these forces combine when the hand flicks the ball forward.
What is the difference between balance and stability?
Balance is the ability of the body to maintain stability when stationary or moving.
Stability is the resistance of the body to be moved.
How could you decrease drag?
Techniques including streamlining, equipment and clothing
How could you lower impulse when catching a ball?
We can cradle the ball to increase the time that the ball spends before it is set into our hands. This creates lower impulse because the incoming force is spread over time.
Name 3 factors that affect the use of levers.
1. Amount of force- more force=greater speed
2. Length of lever- the longer the greater the speed
3. Inertia of the lever- greater weight= more difficult
Explain the magnus effect and the effect in backspin.
When there is an area of low pressure and high pressure around the ball. The ball moves towards the area of lowest pressure and drag is created behind the object.
In backspin, the ball moves upward (low pressure) and when it hits the ground, it will bounce toward where it came from.
When could instability be a good thing?
It can create velocity.