Kinematics

Question 1

What is the difference between scalar and vector quantities?

Answer 1

Scalar quatities only have magnitude but vector quantities have both magnitude and direction.

Question 2

What is the difference between distance and displacement?

Answer 2

Distance is the length of travel along the entire journey, regardless of direction. Displacement is the distance of the straight line of travel of an object from its rest position to its end position(shortest distance).

Question 3

What is the formula for uniform speed?

Answer 3

speed = distance/time (d/t)

Question 4

What is the formula for uniform velocity?

Answer 4

velocity = displacement/time (s/t)

Question 5

What is the common SI unit for both velocity and speed?

Answer 5

m s^-1
(metres per second)

Question 6

What is an instantaneous speed and how do you measure it on a distance-time graph?

Answer 6

It is the speed of an object at a particular instant, which is the gradient of the tangent at that point on the distance-time graph.

Question 7

What is the formula for average speed?

Answer 7

total distance travelled/total time taken

Question 8

Define acceleration.

Answer 8

Acceleration is the rate of change of VELOCITY.
[not speed, acceleration is a vector quantity]

Question 9

What is the formula for uniform acceleration?

Answer 9

acceleration = change in velocity/time period
OR
final velocity-initial velocity/time period

Question 10

From a displacement-time graph, what are the pieces of information you can gain and through what methods do you gain them?

Answer 10

Displacement can be read from the corresponding y-value on the s-t graph.
Velocity at any particular time can be calculated from the gradient of the s-t graph at that point.

Question 11

What information can you get from a displacement-time graph and how do you get it?

Answer 11

Displacement: area under s-t graph
Velocity: corresponding y-axis value of that point on the graph
Acceleration: gradient of the graph at that point

Question 12

What is the value for acceleration due to gravity?

Answer 12

a = g = 9.81ms^2 ~~10ms^2

Question 13

What does air resistance do?

Answer 13

It:
1. opposes the motion of moving objects
2. increases with speed of the object
3. increases with effective surface area of the object
4. increases with density of air
5. has a more significant effect on light objects with large surface area