physics 901-905

Question 1

6 kinematics equations plus acceleration formula

Answer 1

s=d/t 
v=ut+at
v2-u2=2as
s= ut + 1/2at^2
s=v+u/2 x t
as= u+v/2
acc =v-u/t

Question 2

6 differences between mass and weight

Answer 2

weight ————————————mass
w=mass x gravity ————- f=ma
si unit= newton ——– si unit- kg
dependent on gravity —— not dependent
vector ————————– scalar
spring scale ———————balalnce scale
force of gravity ————– amount of matter

Question 3

prefix table

Answer 3

giga-9 
mega - 6
kilo - 3
deci - -1
centi - -2
mili - -3
micro - -6
nano - -9

Question 4

principle of conservation of energy

Answer 4

energy cannot be created nor destroyed, it can only be changed from one form to another

Question 5

density - formula, definition, si unit

Answer 5

definition - mass per unit volume
formula - mass/volume
si unit - kg/m3

Question 6

formula of gravitational potential energy

Answer 6

gpe = mgh (mass x gravity x height)

Question 7

difference between scalar and vector quantities

Answer 7

scalar - magnitude only , vector - magnitude and direction

Question 8

name 5 renewable energy sources

Answer 8

wind energy, tidal energy, geothermal energy, solar energy, wave energy, biomass energy, biofuels and hydroelectric energy

Question 9

name 2 non renewable energy sources

Answer 9

fossil fuels and nuclear fuels

Question 10

momentum formula

Answer 10

mass x velocity

Question 11

impulsive force definition and formula

Answer 11

rate of change of momentum, formula = (mv-mu)/t

Question 12

newtons first law

Answer 12

if an object is at rest it will continue to rest, if an object is in motion it will move at constant velocity unless a force acts upon it / tendency of an object to remain unchanged

Question 13

newtons second law

Answer 13

momentum is directly proportional to the resultant force acting on it

Question 14

difference between static and sliding friction

Answer 14

static friction - friction that exists between a stationary object and the surface it rests on
sliding friction- occurs when drag of two objects being pressed together while moving in opposite directions

Question 15

hooke’s law

Answer 15

states that below the elasticity limit of a spring, extension is directly proportional to force (resultant force = spring constant x extension)

Question 16

conditions of equilibrium

Answer 16

1) sum of forces acting in one direction = sum of forces acting in opposite direction (resultant force = 0)
2) sum of anticlockwise movement = sum of clockwise movement (resultant movement = 0 )

Question 17

moment formula

Answer 17

moment = distance from pivot x force

Question 18

kinetic energy formula, si unit and definition

Answer 18

formula: 1/2 x mass x (velocity)^2
si unit: joule
definition: energy due to motion

Question 19

efficiency formula

Answer 19

(output power x imput power) x 100%

Question 20

work done formula

Answer 20

work done = force x displacement

Question 21

power formula

Answer 21

work done/ time taken or (force x displacement)/time taken

Question 22

pressure formula, definiton

Answer 22

formula: pressure = force/ area
definition: force acting per unit area

Question 23

state pascals principle

Answer 23

pressure=constant, pressure change in one part is transmitted without loss to every portion of the fluid and to the container walls. (f1/a1=f2/a2)

Question 24

boyle’s law

Answer 24

• for a constant mass of gas
• at constant kelvin temperature
• pressure is inversely proportional to volume
• P1V1=P2V2

Question 25

atmospheric pressure formula

Answer 25

density x gravitational field strength x height(pgh)

Question 26

impulse formula

Answer 26

resultant force x time