Nat 5 - Dynamics

Question 1

Name 5 scalars

Answer 1

Distance
Speed
Mass
Time
Energy

Question 2

Name 5 vectors

Answer 2

Displacement
Velocity
Acceleration
Force
Weight

Question 3

What is displacement

Answer 3

How far an object travels in a certain direction.

Question 4

What is the difference between speed and velocity

Answer 4

Speed is the distance travelled per unit time
Velocity is the displacement per unit time

Question 5

How do you find the magnitude of a vector

Answer 5

Pythagoras

Question 6

How do you find the resultant vector

Answer 6

Add or take a way from each other

Question 7

How do you find the direction of the vector

Answer 7

tan0= opp over adj

Question 8

What is the instantaneous speed

Answer 8

The speed at which an object travels in each instant of time. e.g speedometer.

Question 9

How do you calculate average speed

Answer 9

total distance over total time

Question 10

How do you calculate velocity

Answer 10

displacement over time

Question 11

How do you calculate average veolcity

Answer 11

total displacement over total time

Question 12

Velocity can have a positive or negative value True or False

Answer 12

True

Question 13

How do you calculate average speed when using a trolley and light gate experiment

Answer 13

distance between light gates
/
time for trolley to pass between light gates

Question 14

How do you measure instantaneous speed using trolley and light gate expermient

Answer 14

length of card
/
time for card to cut beam

Question 15

A steeper slope on a V-T graph means

Answer 15

A greater acceleration

Question 16

A positive slope on a V-T graph means what

Answer 16

Increasing velocity or the object is accelerating.

Question 17

A negative slope on a V-T graph means what

Answer 17

Decreasing velocity or the object is decelerating

Question 18

A horizontal line on a V-T graph means

Answer 18

The object is moving with a constant velocity

Question 19

How do you find the displacement (or distance travelled) from a V-T graph.

Answer 19

The area under a V-T graph

Question 20

What is acceleration defined as

Answer 20

The rate of change of velocity

Question 21

How do you work out the acclertation

Answer 21

acceleration = v-u over t
V= Final velocity
u= Initial velocity
T= time

Question 22

How do you calculate acceleration from a V-T graph

Answer 22

find the gradient =⯅y
—-
⯅x

Question 23

What is newtons first law

Answer 23

An object will remain at rest or continue to move with constant velocity unless acted on by an unbalanced force

Question 24

If the moon orbits the earth at a constant speed of 2000 mph. Is this an example of Newtons first law. Yes or No

Answer 24

No because newtons first law states it must move with a constant velocity,

And because the moon is constantly orbiting earth its direction is always changing.

Question 25

What is frictional force

Answer 25

a force that opposes motion

Question 26

If an object moves at a constant velocity, the forces are...

Answer 26

Balanced

Question 27

Newtons second law

Answer 27

The acceleration of a body is proportional to the unbalanced force acting upon it and inversely proportion to the objects mass.

Question 28

How do you calculate the unbalanced force.

Answer 28

F=ma

Question 29

How do you calculate the weight

Answer 29

W=mg

Question 30

Newtons third law

Answer 30

If object A exerts a force on object B, then object B exerts an equal and opposite force on object A

Question 31

Give an example of newtons third law

Answer 31

A person is sitting on a chair: The person exerts a force on the chair and the chair exerts an equal but oppsite reaction on the person.

Question 32

Explain the stages of free fall and terminal velocity in terms of newtons laws

Answer 32

When an object falls out of a plane The object accelerates due to gravity Eventually the object in free fall will reach terminal velocity At terminal velocity weight is equal and opposite to air resistance Forces are balanced and object falls at constant velocity.

Question 33

Energy

Answer 33

Energy cannot be created or destroyed. Energy can only be converted from one form of energy to another and energy can then be transferred.

Question 34

What is work done and how do you calculate it

Answer 34

Work done is a measure of the energy required to move an object through a distance. Ew = F d

Question 35

What is gravitational potential energy and how do you calculate it

Answer 35

Gravitational potential energy is the energy an object has by virtue of its position above the surface of the Earth Ep=mgh

Question 36

What is kinetic energy and how do you calculate it

Answer 36

Kinetic energy is the energy an object possesses due to it's motion. Ek = ½mv2

Question 37

How is projectile motion analysed?

Answer 37

Horizontal = constant velocity Vertical = constant acceleration (gravity)

Question 38

How do you calculate horizontal velocity?

Answer 38

v=s/t (constant)

Question 39

What is the vertical acceleration in projectile motion

Answer 39

g = 9.8 m/s² (downwards)

Question 40

How do you find vertical velocity

Answer 40

v=u+at