Linear Motions

Question 1

What is speed?

Answer 1

it is the measure of how fast something moves;

speed is defined as the distance covered per unit of time

Question 2

What is speed measured by?

Answer 2

measured by a unit of distance divided by a unit of time

speed = distance/time

Question 3

What is instantaneous speed?

Answer 3

it is the speed at any instant

Question 4

What is instantaneous speed measured by?

Answer 4

a speedometer

Question 5

What is average speed?

Answer 5

it is the whole distance covered divided by the total time of travel

Question 6

What doesn’t average speed indicate?

Answer 6

it does not indicate the different speeds and variations that may have taken place during shorter time intervals

Question 7

What is the equation for calculating average speed?

Answer 7

average speed= total distance covered/ time interval

Question 8

What is velocity?

Answer 8

the speed of an object and specification of its distance of motion
-speed and direction of motion

Question 9

What does constant velocity mean?

Answer 9

constant speed, no change in direction

Question 10

Is a car moving round a circular motion, in constant velocity?

Answer 10

No, although it may be moving in a constant speed, it is changing direction

Question 11

What does it mean by constant speed and constant velocity? are they the same?

Answer 11

When something moves at constant velocity or constant speed, then equal distances are covered in equal intervals of time

Question 12

What does acceleration mean?

Answer 12

the rate at which velocity changes with time; the change in velocity may be in magnitude or direction or both

Question 13

What is the equation for acceleration?

Answer 13

change in velocity/ interval of time

Question 14

What is acceleration measured in?

Answer 14

the time unit is entered twice: one for the unit of velocity and again for the interval of time in which the velocity is changing
eg. 10 km/h.s

Question 15

Do we accelerate everytime we move in a curved path?

Answer 15

yes , even if we are moving in a constant speed, because our direction is changing, velocity is changing

Question 16

What exceptions can we make with speed, velocity and acceleration when we are moving in a straight line?

Answer 16

When straight line motion is being considered, it is common to use speed and velocity interchangeably.

When direction is not changing, acceleration may be expressed as the rate at which speed changes:

acceleration = change in speed/ interval of time

Question 17

How do you calculate instantaneous velocity?

Answer 17

velocity acquired = acceleration X time

Question 18

What does free fall mean?

Answer 18

Motion under the influence of gravity only

Question 19

Normally, how much does a free falling object accelerate by, per second?

Answer 19

9.8 m/s^2

can be rounded off to 10 m/s^2

Question 20

What is acceleration annotated as in free fall?

Answer 20

g

Question 21

express the equation of velocity acquired (instantaneous velocity) in free fall , from rest?

Answer 21

v = gt

Question 22

what happens to the instantaneous speeds of an object when it is in equal elevation in the path?

Answer 22

the instantaneous speed is the same however the velocities will be opposite; since one has gone up (eg. a ball) while the other is down

Question 23

express the equation for distance fallen in free fall from rest?

Answer 23

d = 1/2gt^2

Question 24

An object falling from free falling: how to calculate distance, from the initial speed and the speed at the first time interval?

Answer 24

first calculate the average speed thus 10-0/2
(/2 because there are two time intervals)
thus average speed is 5 m/s.
thus there is a 5 meter distance covered per second