Mechanics - 1 SAQ questions plus biomechnics unit 1 SAQ questions

Question 1

What are the 3 main base SI units that we need to know ?

Answer 1

1. The metre (m) - the standard unit of length
2. The second (s) - the standard unit of time
3. The kilogram (kg) - the standard unit of mass

Question 2

List three scale factors and their symbol and multiplication factor

Answer 2

• mega (M), 1 000 000 = 10⁶
• kilo (k), 1 000 = 10³
• centi (c), 0.01 = 10^-2
• milli (m), 0.001 = 10^-3
• micro (µ), 0.000 001 = 10^-6
• nano (n), 0.000 000 001= 10^-9

Question 3

BioMick’s forearm is 0.27m in length. Express it using the following scales: kilometres, centimetres, millimetres and micrometres - which scales are the most appropriate ?

Answer 3

• In Km = 2.7x10^-4
• In cm = 27cm
• In mm = 270
• In micrometres = 2.7x10⁵

The cm, mm (&m) scales are the most appropriate scales to use as the numbers are of an easily readable and manageable form

Question 4

1. Convert 1.0 rad into degrees
2. Convert 25 degrees into radians

Answer 4

1. Ans = 57 degrees
2. Ans = 0.44 rads

Worked example is in page 4 of mechanics binder

Question 5

Convert the following into degrees of radians:

1. 360 degrees into radians
2. 90 degrees into radians
3. π into degrees
4. 30 degrees into radians
5. 0.7854 rads into degrees

Answer 5

1. 2π
2. 1/2π
3. 180 degrees
4. 1/6π
5. 45 degrees

Question 6

Describe the difference between vector and scalar quantities

Answer 6

• A scalar is a quantity that has a magnitude only
• A vector is a quantity that has a magnitude and direction

Question 7

Do Page 8 of binder SAQ 4

Question 8

Do page 9 SAQ 5

Question 9

Do Pg. 11 SAQ 6

Question 10

Why are the axes of the cartesian system orthogonal ?

Answer 10

Because orthogonal axes are independent of each other; so a change in one position on one axis does not result in a change in position on another axis

Question 11

Draw a rectangular reference frame and a y-z plane which passes through the point x = 0

Answer 11

Ans is in the binder at the answer bit for SAQ 7

Question 12

Do Pg 15 SAQ 8 in the binder

Question 13

For each of the following write down how many degrees of translational and rotational freedom there are:

• A sliding window
• A door handle
• A hip joint
• A knee joint
• A snooker ball moving on a table
• A drawer

Answer 13

• A sliding window - translational 1, rotational 0
• A door handle - translational 0, rotational 1
• A hip joint - translational 0, rotational 3
• A knee joint - translational 0, rotational 1
• A snooker ball moving on a table - translational 2, rotational 3
• A drawer - translational 1, rotational 0

Question 14

BiomechAnnie takes 2 mins to walk 180m along a straight line.

Calculate her average velocity

Answer 14

Ans = 1.5 m s^-1

Question 15

Do SAQ 11 pg.20

Answer 15

Ans =

Question 16

Do SAQ 12 pg.24