Forces

Question 1

What are newtons law of motion?

Answer 1

1. The law of inertia
2. The law of acceleration
   3.the law of reaction

Question 2

What Is the law of inertia?

Answer 2

A body continues in state of rest or uniform velocity unless acted upon by an external or unbalanced force

Question 3

What is an example of the law of inertia?

Answer 3

A ball will remain on the penalty spot until a force is applied by the foot

Question 4

What Is the law of acceleration?

Answer 4

A body’s rate of change of momentum is proportional to the size of the force applied and acts in the same direction as that force

Question 5

What’s an example of the law of acceleration?

Answer 5

The greater the force applied by the foot the faster the football will accelerate

Question 6

What is the law of reaction?

Answer 6

For every force applied to an object there is an equal and opposite reaction

Question 7

What is an example of the law of reaction?

Answer 7

In football, when the force is applied by the foot to the ball, there is an equal and opposite force applied from the ball to the foot

Question 8

Name the 4 key things that influences newtons laws?

Answer 8

1. Velocity
2. Momentum
3. Acceleration
4. Force

Question 9

What is velocity?

Answer 9

The rate of change of displacement

(Displacement is the shortest straight line route between two points)

Question 10

What is the equation for velocity and the units?

Answer 10

Velocity= displacement/ time taken

Velocity = meters per second
Displacement = meters
Time taken in seconds

Question 11

What is momentum?

Answer 11

The quantity of motion possessed by a moving object

Question 12

What is the equation for momentum, with the units?

Answer 12

Mass X velocity

Momentum= Kgm/s
Mass= kg
Velocity = M/s

Question 13

What is force?

Answer 13

As a push or pull that alters the state of motion of an object

Question 14

What is the equation for force with the units?

Answer 14

Mass X acceleration

Force= newton
Mass = kg
Acceleration = m/s/s

Question 15

What does it mean if the net force is zero?

Answer 15

No change in motion of the body and forces are balanced

Question 16

What is the centre of mass?

Answer 16

An imaginary point at which a body is balanced in a all directions

Question 17

Describe factors which affect balance?

Answer 17

• lower your centre of mass the more balanced you are

-line of gravity- CoM directly above the base of support= high levels of balance

-wide base of support= high levels of balance

• raising your CoM at take off for a jump= body remain in the air for longer

Question 18

How can we widen the base of support to increase stability in martial arts?

Answer 18

Widen the stance in martial art

Question 19

How can the centre of mass in gymnastics be lowered to increase stability?

Answer 19

Gymnast will bend their knees on landing to make sure they are more stable and don’t take a step

Question 20

How can the line of gravity be more centralised to make sure the CoM is over the base of support in netball ?

Answer 20

In netball a shooter will aim to keep her CoM right above her Base of support so she shoots from a stable position

Question 21

What is the effect of the mass of the body on stability?

Answer 21

The greater the mass the greater, the greater the inertia= more stability

Question 22

What’s an advantage of using the flosby flop technique when doing the high jump?

Answer 22

-jumps over bar backwards so back faces down on the bar so centre of mass is outside the body and under the bar, when clearing the bar

-this means he can jump higher using less energy, because only needs to get the body over the bar, centre of mass passes under

Question 23

How and when is stability reduced?

Answer 23

-Rugby when swerving a defender- one point of contact=no line of gravity, centre of mass isn’t over base of support, narrow base of support= increased agility

-sprint start- one point of contact= centre of mass isn’t over base of support, small base of support, no line of gravity- increased acceleration and deceleration

Question 24

What is net force?

Answer 24

Sum of all forces acting upon the body

Question 25

What are the 4 external forces that take place?

Answer 25

-weight
-reaction
-friction
-air resistance

Question 26

What are the horizontal forces on a free body diagram?

Answer 26

-friction
-air resistance

Question 27

What is friction?

Answer 27

Force that opposes the motion of two surfaces in contact

Question 28

What factors affect friction?

Answer 28

-Roughness of the surfaces in contact

-temperature of surfaces in contact

-size of normal reaction

Question 29

What is air resistance?

Answer 29

The force that opposes the motion of a body travelling through the air

Question 30

What factors affect air resistance?

Answer 30

• velocity of the body
  -shape of the body
  -frontal cross-sectional area
• smoothness of the surface

Question 31

How do individuals reduce air resistance?

Answer 31

-Large performers lie flat as possible to reduce frontal cross section

-wears smooth clothing to reduce air resistance

-paragliding=the larger the cross sectional the better

Question 32

Describe how F1 cars create minimum air resistance and maximum friction?

Answer 32

-drivers swerve around on warm up lap to increase the temperature in the tyres to increase friction.

-aerofoil shape adds downward force to increase friction

-frontal cross sectional area is minimal to reduce air resistance

Question 33

What is an example of increasing roughness of surface and the contact surface to increase friction?

Answer 33

-Increase roughness of surface- track runners run on rubberish and rough track= more grip

-roughness of contact surface- sprinters wear spike to increase roughness of contact surface