CH1: Physical Quantities, Units and Measurements

Question 1

list the 6 base quantities with its SI units

Answer 1

length, m
mass, kg
time, s
electric current, A
temperature, K (Kelvin)
amount of substance, mol

Question 2

list the 6 derived quantities

Answer 2

area, m2
volume, m3
speed, m/s
velocity, m/s
acceleration, m/s2
density, kg/m3

Question 3

list the prefixes and its value in the ascending order

Answer 3

nano (10^-9)
micro (10^-6)
milli (10^-3)
centi (10^-2)
deci (10^-1)
kilo (10^3)
Mega (10^6)
Giga (10^9)
Tera (10^12)

Question 4

definition of period

Answer 4

time taken for a pendulum to complete one full oscillation from point A to point B back to point A.

Question 5

symbol, SI unit of period and its d.p.

Answer 5

symbol: T
SI unit: seconds (s)
2 d.p.

Question 6

instrument used to measure period

Answer 6

digital stopwatch

Question 7

what affects the period of a pendulum?

Answer 7

the length of pendulum

Question 8

what does not affect the period of a pendulum?

Answer 8

mass of the pendulum and angle of its swing

Question 9

diameter of Earth

Answer 9

10^7 m

Question 10

definition of scalar

Answer 10

quantities that only have magnitude

Question 11

definition of vector

Answer 11

quantities which have magnitude and direction

Question 12

list the 6 scalar quantities

Answer 12

distance, mass, speed, time, temperature, pressure

Question 13

list the 6 vector quantities

Answer 13

displacement, velocity, weight, force, acceleration, moment

Question 14

how to calculate average speed?

Answer 14

total distance/total time

Question 15

acceleration formula

Answer 15

(v-u)/t
or
(final velocity - initial velocity)/time taken

Question 16

what is the gradient of a velocity-time graph?

Answer 16

acceleration

Question 17

how to calculate distance in a velocity-time graph?

Answer 17

area under graph
(it is also the formula for calculating distance in graphs)

Question 18

what is the gradient of a distance-time graph?

Answer 18

speed

Question 19

what happens when object falls with air resistance?

Answer 19

object will experience air resistance as its speed increases. When air resistance = weight of object, object will fall at a constant speed. This means that acceleration is 0 m/s^2.

Question 20

what happens to the speed and acceleration when there is no air resistance?

Answer 20

speed will become constant.
acceleration = 10 m/s^2