application of forces and transfer of energy Flashcards
(54 cards)
1
Q
what is a force
A
a pull or a push that acts upon an object as a result of its interaction with a another object
2
Q
types of forces
A
- contact forces
- non-contact forces
3
Q
types of contact forces
A
- friction
- elastic
4
Q
types of non-contact forces
A
- magnetic
- gravitational
5
Q
what is weight
A
weight is the measure of the gravitational force acting on a object
6
Q
what is mass
A
the amount of matter in an object
7
Q
how does your weight change
A
when you enter a place with a different gravitational pull/force
8
Q
how does your mass change
A
it doesn’t
9
Q
SI unit for weight
A
newton (N)
10
Q
SI unit for mass
A
Kg
10
Q
what can be used to measure weight
A
spring balance
11
Q
what can be used to measure mass
A
- electronic balance
- beam balance
12
Q
what are the effects of force
A
- move a stationary object
- change the speed of an abject
- change the direction in which an object moves
- stop a moving object
13
Q
what are the properties of a balanced force
A
- net force acting on the object equals zero
- either remains at rest
- or moves with constant speed
14
Q
what is a unbalanced force
A
- net force acting on object does not equal zero
- either changes its speed
- or changes direction of motion
- or both
15
Q
how to calculate resultant force
A
- resultant force - magnitude(amount of force) + direction
- are forces balanced
- motion of box
16
Q
calculating mass and weight
A
W=m x g
W=weight
m=mass, in kg
g= gravitational force, in 10n/kg
17
Q
what is required in a force
A
- energy
- matter
17
Q
what is the pivot in a turning object
A
the object that is the point at which the force goes around
18
Q
what is the force in a turning object
A
object turning the pivot
19
Q
what affects pressure
A
surface area
20
Q
how to calculate pressure
A
pressure=force (weight) /area
20
Q
what is pressure
A
effect of force acting on an object
21
Q
what is the unit for pressure
A
n/m2
pascal (Pa)
22
what is pressure defined as
the force executed per unit area
22
will there be more pressure applied on a smaller area of contact or a larger area of contact
- smaller area of contact
- more pressure is applied
23
why do we need to draw arrows in a free body diagram
- to show the direction of the force
- force always has a direction
23
what are the 2 necessary arrows in free body diagram
- gravitational force (arrow downwards)
- normal contact force (arrow upwards
23
calculate work
work (J)= force (N) x distance moved in direction of force (m)
23
cases when zero work is done
- object doesn't move when force is applied
- object moves at constant speed when no force is applied
- distance moved by the object is perpendicular to the direction of an applied force
23
forms of energy
- fossil fuels
- solar energy
- hydroelectric energy
- wind energy
- geothermal energy
- biofuels
- nuclear energy
24
what are fossil fuels
- oil, coal, natural gas
- formed from the remains of dead plants and animals buried in Earth millions of years ago. Hence, they are limited and will run out one day.
25
what is the Impact on the environment fossil fuels have
releases air pollutants and greenhouse gases (which contribute to global warming and increases the rate of climate change) , can cause natural disasters to be more intense.
26
what is the energy conversion in fossil fuels
chemical potential energy (fossil fuels) → heat energy → kinetic energy (turbine) → electrical energy (generator)
27
what is solar energy
- energy from the sun
- We can use solar panels to harness solar energy from the sun, they are made of materials that capture sunlight and convert light energy into electrical energy.
28
what is the Impact on the environment solar energy has
- Solar energy can generate electricity without releasing air pollutants and greenhouse gases, the process of harnessing solar energy has minimal impact on the environment.
- However, care needs to be taken to reduce the amount of toxic waste generated during the production and disposal of solar panels.
29
what is the energy conversion in solar energy
light energy (the sun) → electrical energy (solar cell)
30
what is hydroelectric energy
the electrical energy generated by turbines when moving water power them
31
what is the energy conversion in hydroelectric energy
gravitational potential energy (water stored behind a dam) → kinetic energy (water) → kinetic energy (turbine) → electrical energy (generator)
32
what is the impact on the environment hydroelectric energy has
generating hydroelectric energy produces very little greenhouse gases. However, the reservoir water floods the area behind a dam, this kills plants and forces animals to move to other areas.
33
what is wind energy
- energy from the wind
- Wind turbines are used to convert the energy from the wind to electrical energy.
34
what is geothermal energy
the use of heat deep inside the earth, producing starting team to turn turbines, hence generating electricity
34
what is the impact on the environment wind energy has
- large plots of land needs to be cleared to build the wind turbines, this destroys the natural habitats of wildlife. Birds also might be killed due to flying into the blades.
- Noise pollution from the turning blades will impact nearby communities.
35
what is the energy conversion in wind energy
kinetic energy (wind) → kinetic energy (wind turbine) → electrical energy (generator)
36
what is the impact on the environment geothermal energy has
requires a lot of clearing of land
37
what is the energy conversion in geothermal energy
heat energy → kinetic energy(of steam) → kinetic energy (of turbines) → electric energy (of turbines)
38
what is biofuels
- Biofuels are fuels that are produced over a short period from biomass.
- They can be produced from plants or biowaste or recycling of food waste (e.g. used cooking oil and plant pulp)
39
what is the impact on the environment biofuels have
- Like fossil fuels, when biofuels are burnt, they release air pollutants such as carbon dioxide.
- These air pollutants that are released are bad for the environment.
40
what is the energy conversion in biofuels
Chemical potential energy of biofuels→ heat energy when burned → kinetic energy in cars
41
what is nuclear energy
- Nuclear energy is the energy harnessed from the nucleus of an atom
- Nuclear energy originates from the splitting of an isotope of uranium, yielding a lot of nuclear energy
42
what is the impact on the environment nuclear energy has
- nuclear energy is a source of clean energy and requires less land space to generate the same amount of energy compared to other alternative sources of energy
- Nuclear energy produces radioactive waste (hazardous waste that contains radioactive material) which can contaminate air, soil, and water is dangerous to human and wildlife health
- Uranium is also a non-renewable resource, and cannot be replenished easily
43
what is the energy conversion in nuclear energy
Nuclear energy → heat energy → kinetic energy → electrical energy
44
what is temperature
measurement of the movement of kinetic energy between particles in an object. The higher the rate, the higher the temperature
45
what is heat
a form of energy
