Forces, Movement And Shape

Question 1

What does a vector quantity have?

Answer 1

Magnitude and direction

Question 2

What does a scalar quantity have ?

Answer 2

Magnitude only

Question 3

What can scalar quantities never be ?

Answer 3

Negative

Question 4

What can forces do to an object to they way it moves?

Answer 4

• objects can accelerate or decelerate

* objects can change direction

Question 5

What can forces do to objects to change their size ?

Answer 5

• objects can be stretched

* objects can be squeezed

Question 6

What is the normal reaction force ?

Answer 6

When an object rests on a solid if feels a reaction force at 90° to the surface

Question 7

Where does upthrust always occur ?

Answer 7

In a fluid

Question 8

What is thrust ?

Answer 8

Thrust is a reaction force
• it occurs when mass is pushed out the back of something causing the object to move toward
• eg rocket

Question 9

What is an electrostatic force ?

Answer 9

Similar charges repel and opposite charges attract

Question 10

What is an magnetic force ?

Answer 10

Like poles repel, opposite poles attract

Question 11

What always happens to weight ?

Answer 11

Weight is always drawn down from the centre of gravity

Question 12

What is the unit for mass?

Answer 12

Kg

Question 13

What is the unit of weight?

Answer 13

N

Question 14

What depends on the strength of the gravitational field ?

Answer 14

Weight, mass doesn’t change

Question 15

What happens to any two objects that have mass?

Answer 15

They will attract each other, the more massive the object the bigger the gravitational force

Question 16

Relation between weight mass and gravitational field strength

Answer 16

Weight = mass x gravitational

Question 17

What is the gravitational field strength on earth?

Answer 17

10 N/kg

Question 18

What is newtons second law?

Answer 18

In the presence of a resultant force a body experiences an acceleration

Question 19

What does resultant mean ?

Answer 19

Overall

Question 20

What overall force does a stationary object have?

Answer 20

No overall force

Question 21

What is the equation linking acceleration, force and mass ?

Answer 21

Acceleration = force/mass

Question 22

If acceleration is equal to force, what is mass?

Answer 22

Constant mass

Question 23

What is force proportional to ?

Answer 23

Acceleration and acceleration is proportional to force

Question 24

Describe terminal velocity

Answer 24

• when object starts falling it is accelerating as weight is much greater than air resistance
• The forces start to balance out however still accelerating but not as quickly
• when weight is equal to air resistance the object stops accelerating and falls at a constant speed, this is called terminal velocity

Question 25

What is stopping distance made up of?

Answer 25

* thinking distance | * braking distance

Question 26

What is thinking distance?

Answer 26

It is the distance travelled whilst the body is reacting to the message it receives from the brain

Question 27

What is braking distance?

Answer 27

It is the distance travelled whilst the car is decelerating to a stop

Question 28

How does the thinking distance increase?

Answer 28

It increases linearly

Question 29

How does braking distance increases?

Answer 29

It increases exponentially

Question 30

What does braking distance depend on?

Answer 30

Speed squared

Question 31

What affects braking distance?

Answer 31

• vehicle condition - brake pads/tyres are worn, braking will take longer • road condition - rain or ice on the road surface will increase braking distance • mass of car - heavier car=take longer to stop ( only use if others can't be used )

Question 32

What affects thinking distance ?

Answer 32

``` • age • drugs/alcohol • fatigue • distraction - they all increase reaction time ```

Question 33

What is the moment of a force?

Answer 33

It Is a measure of the forces turning effect

Question 34

What will forces with a big moment have ?

Answer 34

Larger turning effect

Question 35

What an two identical forces have?

Answer 35

They can have entirely different moments

Question 36

What is the equation linking force, moment and perpendicular distance from pivot ?

Answer 36

Moment = force x distance

Question 37

What is the principle of moment ?

Answer 37

In equilibrium moments anticlockwise equals moments clockwise

Question 38

What is the equation linking 2 forces and 2 perpendicular distances ?

Answer 38

F1d1 = F2d2

Question 39

What is the centre of mass ?

Answer 39

It is an imaginary point through which all the mass of an object can be said to act

Question 40

What will an object do around the centre of mass ?

Answer 40

Rotate

Question 41

what will cause a object to fall over?

Answer 41

When an object's centre of mass falls outside its base the object will topple over

Question 42

What is hooks law?

Answer 42

That the extension of a spring is proportional to the load

Question 43

What also about hooks law but only at the beginning?

Answer 43

A wire and rubber band

Question 44

What equation links force, spring constant and extension ?

Answer 44

Force=spring constant x extension

Question 45

What is the spring constant measured in ?

Answer 45

Newtons per metre (N/m)

Question 46

What is the spring constant ?

Answer 46

The "stiffness" of a spring

Question 47

What does a large spring constant indicate and what does a small spring constant indicate ?

Answer 47

* Large spring constant = very stiff spring | * small spring constant = very loose spring

Question 48

What happens when you stretch a spring to its elastic limit ?

Answer 48

It won't go back to its original shape

Question 49

What is elastic behaviour ?

Answer 49

When you stretch and object with this behaviour it will return to its original shape