Ch 2 Kinematics

Question 1

Distance

Answer 1

It is the length of the path travelled by the object.

Question 2

What is displacement?

Answer 2

Displacement is the change in position of an object.

It is also equal to the shortest distance between two points. This distance is written down with a direction making it a vector quantity.

Question 3

What are the differences between distance and displacement?

Answer 3

Distance: depends on the path, always positive
Displacement: independent of the path taken, can be positive or negative

Question 4

What is speed?

Answer 4

Speed is rate of change of distance.

It is a scalar quantity so has no mention of direction.

Question 5

What is velocity?

Answer 5

Velocity is the rate of change of displacement.

It is a vector quantity.

Question 6

What is acceleration?

Answer 6

Rate of the change in velocity.

It is a vector quantity.

Question 7

What is Average speed?

Answer 7

Average speed is the total distance travelled over a time interval and is measured in meters per second.

Question 8

uniform acceleration

Answer 8

Rate of change of velocity is constant.

An object travelling with a uniform acceleration of 5m/s² experiences an increase in its velocity by 5m/s every 1 sec.

An object travelling with a uniform acceleration of -5m/s² experiences a decrease in its velocity by 5m/s every 1 sec.

Question 9

non-uniform acceleration

Answer 9

when the magnitude of acceleration changes over time.

Question 10

acceleration of free-fall for a body near to the Earth is __________ and is approximately ________ m/ s²

Answer 10

constant , 10

Question 11

What is the formula for acceleration?

Answer 11

Change in velocity/ Time Taken

a=(v-u)/t

Question 12

Instantaneous

Answer 12

at a specific point in time.

Question 13

For a distance-time graph, the _________ never decreases.

Answer 13

distance; it either increases or remains the same

Question 14

When the object is stationary, the distance-time graph will be ________ line.

Answer 14

Horizontal

Question 15

The gradient of a distance-time graph is the ________________ of the object.

Answer 15

Instantenous Speed

Question 16

For straight line with positive gradient, it means that the object is travelling at _________ speed

Answer 16

Uniform

Question 17

For curves, it means that the object is travelling at ____________ speed

Answer 17

Non-uniform

Question 18

deceleration is

Answer 18

negative acceleration

Question 19

the area under a speed-time graph to determine the _______________ for motion with uniform speed or uniform acceleration.

Answer 19

Distance Travelled

Question 20

In the absence of air resistance, all objects fall with the same acceleration, regardless of their mass.

(True/False)

Answer 20

True

Question 21

So long as air resistance remains insignificant, the speed of a falling object will increase at a ________ rate, getting larger the longer it falls for.

Answer 21

Steady/uniform/constant

Question 22

When a parachutist jumps out of an aeroplane, two main forces act:

1. Weight (the force of gravity)
2. ______________

Answer 22

Air resistance

Question 23

For a speed time graph:

1. If the line is horizontal, the speed is _________ and value of acceleration is ___________.
2. If the line slopes upwards then the object is ___________
3. If the line goes down then the object is _____________

Answer 23

1. constant, zero
2. accelerating (speeding up)
3. decelerating (slowing down)

Question 24

When asked to find the distance, start by stating:

distance = area beneath graph

A common mistake is to try and find distance using the distance-speed-time equation. This equation will not work if the _________ is changing.

Answer 24

speed of the object

Question 25

For a speed-time graph

If the gradient of the line changes then the acceleration of the body must be changing:

A line with constant gradient represents -__________ acceleration (linear motion)

A curved line represents ___________ acceleration – either decreasing (if the gradient gets ________) or increasing (if the gradient gets large)

Answer 25

constant,smaller

Question 26

Incase of circular motion, The speed remains ____________ but __________ changes at every point.

Answer 26

speed, velocity

Question 27

The direction of velocity is ___________ to the circular path.

Answer 27

Tangent