Kinematics

Question 1

What is a scalar?

Answer 1

A quantity that has magnitude (size/amount) only. No direction. ex: coin diameter, mass

Question 2

What is a vector?

Answer 2

(->)
A quantity that is represented by an arrow describing both direction and magnitude. Ex: force

Question 3

What is Distance?

Answer 3

(∆d)
A scalar quantity. Describes the length of the path taken between two points.
Depends on the route taken, doesn’t have to be direct, you can take a large detour.

Question 4

What is Displacement?

Answer 4

(∆d with ->)
A vector quantity. The shortest straight line distance from one point to another. Depends on the start and finish only, not the route.
(∆d-> = ∆f-> (final position) - ∆i-> (initial position))

Question 5

What is ∆?

Answer 5

Symbol for delta. “Change in”

Question 6

What is Position?

Answer 6

A vector quantity. Describes a specific point relative to a reference point.
Ex:
- yards in a football field (a position, reference point is endzone)
- units on a coordinate plane (a position, reference point is the origin)

Question 7

What is a collinear vector?

Answer 7

It means you can only add vectors that share a line. If they are not on the same line, you have to add them separately.

Question 8

Compare using ∆ for points vs. parts of a journey.

Answer 8

You do not use ∆ for points, but you use ∆ for the parts of a journey

Question 9

What is the formula for V(avg)

Answer 9

V(avg) = (d total) / (t total)

Question 10

What is (average) speed?

Answer 10

V
ONLY APPLICABLE WHEN TRAVELLING AT A CONSTANT SPEED (UNIFORM MOTION)
A scalar quantity that represents the distance an object travels during a specific time interval.

Question 11

What is (average) velocity)?

Answer 11

V (->)
ONLY APPLICABLE WHEN TRAVELLING AT A CONSTANT SPEED (UNIFORM MOTION)
A vector quantity (with direction) that shows the displacement of an object during a specific time interval.

Question 12

Name the 7 rules/steps of graphing.

Answer 12

1. Done in pencil
2. Meaningful title (y vs x (Time always on x) for ___)
3. Draw and label axis (manipulated variable on x-axis, responding on y-axis)
4. Choose scales that are easy to use (50%-100% of total sheet is fine)
5. Points made clear and circled
6. Line of best fit, a linear line, closest to actual points (a trend line)
7. Legend if more than one set of data
   *8. (if needed) Slope = y2-y1 / x2-x1, ∆d/∆t, use actual points on graph (not from data), no sig. digs required because you do that

Question 13

What unit does the slope represent for a distance-time graph?

Answer 13

Velocity (because of negative slope).

Question 14

What is acceleration?

Answer 14

a (->)
Change in speed over a period of time. Occurs when an object changes its velocity. It is a vector since it has direction. This is why we can’t always use v = d/t, since objects mostly don’t have uniform motion.

Question 15

What is the graphing formula for acceleration?

Answer 15

Slope = ∆v /∆t

For accelerated motion, a distance-time graph will be curved, because the velocity is changing for each time interval.

On a v (->) vs t graph, a straight line will mean constant speed. A slope will mean acceleration (either forward or backward, or deacceleration)

Question 16

On a d (->) vs. t graph, what does the slope give us?

Answer 16

Velocity

Question 17

On a d (->) vs. t graph, what does the area below the line give us?

Answer 17

Nothing of use

Question 18

On a v (->) vs. t graph, what does the slope give us

Answer 18

Acceleration

Question 19

On a v (->) vs. t graph, what does the area below the line give us?

Answer 19

∆d(->)

Question 20

What are the 7 steps of the Scientific Method?

Answer 20

1. The Question (Subjective or Objective)
2. Background Information (Identify Variables, Qualitative or Quantitative)
3. Hypothesis
4. Experimental Design (Validity, Reliability)
5. Results (Graph?)
6. Data Analysis (Graph, Average)
7. Conclusion (Review Intent, State whether results support the hypothesis, Evaluate procedure and possible improvements, Identity Sources of Error)

Question 21

What are some basic significant digit rules?

Answer 21

• The # of is: All digits after the first non-zero digit (from left to right)
• Counting objects has infinite
• Measurements and conversions have to be kept constant (1 kg to 1000g, still only 1 sig. dig. Could be as 1 x 10^3 instead)

Question 22

What is scientific notation?

Answer 22

Ex: 1785.2 to 3 sig. digs.
1.7852 x 10^3
1.79 x 10^3

Question 23

What is dimensional analysis?

Answer 23

Ex: How many quarters in $2.25?
$2.25 x 4 quarters / $ 1 (this is the conversation factor). = 9 quarters
You put the unit that you are trying to convert in the denominator so they cancel out (that’s how you know you are doing it right).

Question 24

How are significant digits used if you are adding/subtracting?

Answer 24

Round calculated answer to the least number of decimal places.
Ex: 0.031 (3 Decimal Places) + 4.20 (2 Decimal Places) = 4.231 ——> 4.23

Question 25

How are significant digits used if you are multiplying/dividing?

Answer 25

Round calculated answer to the same number of significant digits as the value with the least number of total significant digits.
Ex: 0.042 (2 SGD) x 3.10 (3 SGD) = 0.1302 ——> 0.13

Question 26

What if you are performing both adding/subtracting and multiplying/subtracting?

Answer 26

Use multiplying rules only.
Ex: 1.34 (3 SGD) x 2.678 (4 SGD) x 5.2 (SGD) = 18.660304 ——> 19

Question 27

What is a time interval?

Answer 27

Amount of time difference between two given times.

∆t = ∆t(f) - ∆t(i)