1. physical quantities and 2 Kinematics

Question 1

Name all the SI base quantities.

Answer 1

Length
mass
time
amount of substance
current
temperature

Question 2

What is the SI unit of -
1. mass
2.length
3. time
4. current
5. temperature

Answer 2

1. Kilogram- kg
2. metre- m
3. seconds- s
4. ampere - A
5. kelvin- k

Question 3

Write all the prefixes and their decimal multiples-
largest to smallest

Answer 3

tera - 10 to the power 12
giga- 10 to the power 9
mega- 10 to the power 6
kilo- 10 to the power 3
centi- 10 to the power -2
milli- 10 to the power -3
micro- 10 to the power -6
nano- 10 to the power -9
pico- 10 to the power -12

Question 4

Define scalar and give all the examples.

Answer 4

Scalar is a quantity only having a MAGNITUDE.
Examples-
speed
distance
mass
time
energy
volume
density
pressure
electric charge
temperature

Question 5

Define the vector and give all its examples.

Answer 5

Vector is a quantity having both magnitude and direction.
Examples-
velocity
displacement
acceleration
force
momentum
weight

Question 6

Define a resultant vector

Answer 6

When two or more vectors are added together or one is subtracted from another , a single vector is formed and is known as the resultant vector

Question 7

What is the condition for equilibrium for vectors?

Answer 7

In equilibrium, there are closed vector triangles. The vectors, when joined together form closed triangle.
If three forces acting on the object are in equilibrium; they form closed triangles.

Question 8

Define random error and the effects random error; and how to reduce them.

Answer 8

Random errors cause unpredictable fluctuations in an instrument’s readings as a result of uncontrollable factors, such as environmental conditions
This affects the precision of the measurements taken, causing a wider spread of results about the mean value
To reduce random error: repeat measurements several times and calculate an average from them

Question 9

Define Systematic error and its effects; and how to reduce it.

Answer 9

Systematic errors arise from the use of faulty instruments used or from flaws in the experimental method
This type of error is repeated every time the instrument is used or the method is followed, which affects the accuracy of all readings obtained
To reduce systematic errors: instruments should be recalibrated or the technique being used should be corrected or adjusted

Question 10

Distinguish between precision and accuracy.

Answer 10

Precision of a measurement: this is how close the measured values are to each other; if a measurement is repeated several times, then they can be described as precise when the values are very similar to.
The precision of a measurement is reflected in the values recorded - measurements to a greater number of decimal places are said to be more precise than those to a whole number
Accuracy: this is how close a measured value is to the true value; the accuracy can be increased by repeating measurements and finding a mean average.

Question 11

What is the formula for calculating percentage uncertainity?

Answer 11

(uncertainity/measured value)*100

Question 12

Combining uncertainities.

Answer 12

1. Adding/subtracting the data= add the absolute uncertainities
   2.multiplying/dividing the data= add the percentage uncertainites
   3.raising to a power= multiply the uncertainity by the power

Question 13

Define:
distance
speed

Answer 13

Distance-the total length between two points
Speed-the total distance travelled per unit time

Question 14

Define:
Displacement
Velocity
Acceleration

Answer 14

Displacement- the distance of an object from a fixed point in a specific direction.
Velocity- The rate of change of displacement of an object
Acceleration- the rate of change of velocity of an object

Question 15

Formulae for-
speed
velocity
acceleration

Answer 15

speed= distance/ time
veloctiy= change in displacement/time
acceleration= change in velocity/ time

Question 16

what does the slope say in the displace-time graph?

Answer 16

VELOCITY

Question 17

What does the slope say on a velocity-time graph?

Answer 17

ACCELERATION

Question 18

What does the area under the velocity time graph represents?

Answer 18

DISPLACEMENT of the moving object

Question 19

Write all the kinematic equations of motion.
‘= to the power.
and what are the conditions to apply these equations of motion?

Answer 19

v= velocity ,u= initial velocity, v= final velocity, s=displacement
t= time interval and a= acceleration
1. v= u+at
2. s=(v+u)/2 *t
3. s=ut+ 1/2 *at’2
4. v’2= u’2+2as

conditions-
1. when the motion of an object is in the straight line
2. an object with constant acceleration

Question 20

Describe uniform and non-uniform acceleration.

Answer 20

Uniform acceleration- when the change in velocity of an object is the same in the same time period
Non-uniform acceleration- when the velocity of an object changes by different amounts in the same period of time.

Question 21

define acceleration of free fall or free fall.

Answer 21

when an object accelerates due to gravity in the absence of any other forces such as air resistance

Question 22

what is the value of free fall=g.

Answer 22

g=9.81 ms-2

Question 23

What are the forces acting on the object travelling in projectile motion ?

Answer 23

only gravity
air resistance is negligibe

Question 24

Three key phrases to remember under projectile motion.

Answer 24

1. time to flight- vertical motion
2. maximum height attained- vertical motion
3. Range- horizontal motion or distance

Question 25

How to calculate time of flight, maximum height attained and range in projectile motion.
Draw and label the diagram of projectile motion.

Answer 25

https://www.savemyexams.co.uk/as/physics/cie/22/revision-notes/2-kinematics/2-1-equations-of-motion/2-1-9-projectile-motion/