Chapter 1 : Kinematics - Describing Motion

Question 1

Two important things to consider when approaching kinematics :

Answer 1

1. Motion of bodies in a straight line

2. Only consider uniform acceleration ( so acceleration that is constant and does change)

Question 2

Definition of displacement

Answer 2

°distance travelled by a body, in a particular/specified direction

°shortest straight line distance between two points

°is the distance of an object from a fixed reference point in a specified direction

Unit : m

Question 3

Definition of distance

Answer 3

°actual length of a path followed by a body

Unit : m

Question 3

Definition of distance

Answer 3

°actual length of a path followed by a body

Unit : m

Question 4

Definition of Speed

Answer 4

° rate of change of distance

° distance travelled per unit time

Unit: ms-1

Question 5

Definition of velocity

Answer 5

° rate of change of displacement

° distance covered by a body in a specified direction (or displacement) per unit time

Unit: ms-1

Question 6

Definition of acceleration

Answer 6

°rate of change of velocity

Unit: ms-2

Question 7

Displacement - time ⌚ graphs :

What is the gradient equal to?

Answer 7

Velocity

Question 8

If the gradient of a displacement - time ⌚ graph is a straight line between the displacement and time the velocity is

Answer 8

Constant

Question 9

The steeper the slope of a displacement–time ⌚ graph the…

Answer 9

Greater the velocity

Question 10

If the slope of a displacement - time ⌚ graph is zero that means 2 things :

Answer 10

1. Displacement is not changing
2. Velocity =0

Therefore the object is not moving

Question 11

If the slope of a displacement - time ⌚ graph suddenly becomes negative it means…

Answer 11

The direction of the object is changing. The object is moving back the way it came

Question 12

If the displacement - time ⌚ graph is curved that means

Answer 12

The velocity is changing and is not constant

Question 13

Definition of vector addition :

Answer 13

°combining 2 or more vector quantities through addition to determine the resultant (the combine effect) of the vectors

Question 14

Definition of a scalar quantity :

Answer 14

A quantity that only has magnitude

Question 15

Definition of a vector quantity :

Answer 15

A quantity that has both magnitude and direction (direction is shown by signs +/- or arrows)

Question 16

All forms of energy (including work done) are scalar/vector quantities?

Answer 16

Scalar

Question 17

Give 7 examples of scalar quantities :

Answer 17

1. mass ⚖
2. time ⌚
3. Temperature 🤒🌡️
4. Distance 🛣️
5. Resistance
6. pressure
7. speed 🛑

Question 18

7 examples of vector quantities :

Answer 18

1. Weight kg
2. acceleration
3. velocity
4. displacement
5. Force
6. Momentum
7. Torque

Question 19

Definition of instantaneous speed :

Answer 19

°the speed of an object measured over a short period of time

Question 20

Definition of instantaneous speed :

Answer 20

°the speed of an object measured over a short period of time

Question 21

NB to know the formula for a trapezium when working the area under a graph.

What is the formula?
How can you derive s=((u+v) /2)x t from it

Answer 21

Area of a trapezium =h/2.(a+b)
°a and b are the heights of the trapezium and h is the base

Think of an v-t graph with a trapezium shaped area….
h= the base which is time ⌚
a= initial velocity u
b= final velocity v

Therefore: t/2.(u +v)
Which is the same as s=((u+v) /2)x t

Question 22

Resolving a vector refers to…?

Answer 22

Splitting a vector which is at an angle to the horizontal into 2 components