unit 2 kinematics

Question 1

speed

Answer 1

change of distance per unit time
scalar quantity
SI unit (m/s)
formula: V= d/t

Question 2

uniform speed

Answer 2

when an object moves at the same speed throughout its journey , it has a uniform speed ( or constant speed)

Question 3

average speed

Answer 3

total distance travelled per total time taken

Question 4

velocity

Answer 4

change of displacement per unit time
vector quantity
SI unit (m/s)
formula: v=d/t

Question 5

average velocity

Answer 5

total displacement / total time taken

Question 6

acceleration

Answer 6

the rate of velocity change
vector quantity
SI unit ( m/s^2)
formula: a= (v-u)/t

Question 7

what does it mean when an object have an constant velocity

Answer 7

zero acceleration

Question 8

uniform acceleration

Answer 8

when the change in the velocity is the same for every unit of time , a moving object is said to have a uniform acceleration

Question 9

distance-time graph

Answer 9

horizontal line - at rest/ stationary
straight line - moving with a constant speed
a curve - moving with changing speed

Question 10

distance time graph ( gradient and steepness)

Answer 10

the gradient is the speed of the graph
the steeper the line, the greater the speed

Question 11

speed-time graph

Answer 11

horizontal line - moving at zero acceleration ( constant speed)
straight line - moving with a constant acceleration
a curve - moving with changing acceleration

Question 12

speed-time graph ( gradient and area)

Answer 12

gradient is the acceleration
the area under the graph is the distance travelled by the moving object
if the graph touches the time-axis , the object is stationary

Question 13

free fall

Answer 13

without air resistance, all objects fall freely with a constant acceleration due to gravity of earth