9 Application of Force and Transfer of Energy Flashcards
What are the two types of forces?
Contact force
Non-contact force
What are contact forces?
Forces that acts between 2 objects in physical contact.
What are non-contact forces?
Forces that acts between 2 objects not touching each other.
Give 2 examples of contact forces.
friction
elastic forces
Give 2 examples of non-contact forces.
gravitational force (weight)
magnetic force
What is the SI unit of force?
newton (N)
What is weight?
It measures the amount of gravitational force on an object.
What is mass?
The amount of matter in a body.
What is the SI unit of mass?
kilogram (kg)
List down 4 differences between mass and weight.
What are they?
Their SI units
Do they change with location?
What is used to measure them?
1) Mass is the amount of matter in a body. Weight is the gravitational force exerted at an object.
2) SI unit of mass: kg. SI unit of weight: N.
3) Mass does not change with location. Weight changes with location.
4) Spring balance is used to measure mass. Beam balance is used to measure weight.
What are the five effects of forces on an object?
1) moves a stationary object
2) stops a moving object
3) changes the direction of motion of a moving object
4) change the shape and size of an object
5) causes an object to turn
What are the two factors that affect the amount of pressure exerted?
You can also think about how to increase pressure exerted on an object.
1) force exerted
2) area of contact
It must be ‘area of contact’ and not just ‘area’ or ‘surface area’.
Increased force and smaller area of contact.
What does it mean when we say ‘energy is conserved’?
Energy is not created or destroyed.
It is transferred from one object to another or converted from one form to another.
What is the SI unit for energy?
joule (J)
State the 7 sources of energy.
1) fossil fuels
2) solar energy
3) hydroeelctric energy
4) wind energy
5) geotherma energy
6) biofuel
7) nuclear energy
State the impact of using fossil fuel on the environment.
impact can be good or bad.
1) release air pollutants and greenhouse gas
2) greenhouse gas contributes to global warming and causes climate changes
State the impact of using solar energy on the environment.
impact can be good or bad.
1) generate electricity without producing pollutants and greenhouse gas.
2) Toxic wastes are produced during the production and disposal of solar panels.
State the impact of using hydroelectric energy on the environment.
impact can be good or bad.
1) produces very little pollutants and greenhouse gas
2) causes flooding in the area behind a dam
State the impact of using wind energy on the environment.
impact can be good or bad.
1) Does not produce pollutants or greenhouse gas.
2) destroy wildlife as large plots of land needed to be cleared.
3) Birds may be killed if they collided into the blades of the wind turbines.
4) Noise pollution for the nearby communities.
State the impact of using geothermal energy on the environment.
impact can be good or bad.
1) Does not produce pollutants or greenhouse gas.
2) destroy wildlife as large plots of land needed to be cleared.
3) Toxic elements underground causes harm to environment if not handled properly.
State the impact of using biofuel on the environment.
impact can be good or bad.
1) release air pollutants and greenhouse gas
2) greenhouse gas contributes to global warming and causes climate changes
3) Helps to recycle and reduces wastes as biofuels can be made from food wastes and used cooking oil.
4) Helps to reduce carbon dioxide in the air as plants are grown to produce biofuels.
State the impact of using nuclear energy on the environment.
impact can be good or bad.
1) Does not produce pollutants or greenhouse gas.
2) Requires less and to build than a solar or wind farm.
3) Needed a lot of effort to research for ways to dispose and store nuclear wastes safely.
What is the energy change in a fossil fuel power plant?
chemical energy -> heat energy -> kinetic energy (turbine) -> electrical energy (generator)
What is the energy change in a hydroelectric power plant?
gravitational potential energy (water behind the dam) -> kinetic energy (water) -> kinetic energy (turbine) -> electrical energy (generator)
What is the energy change in a wind power plant?
kinetic energy (wind) -> kinetic energy (turbine) -> electrical energy (generator)
What is the energy change in a geothermal power plant?
heat energy (earth’s core) -> kinetic energy (steam) -> kinetic energy (turbine) -> electrical energy (generator)
What is the energy change in a nuclear power plant?
nuclear energy (atoms) -> heat energy -> kinetic energy (turbine) -> electrical energy (generator)
What is the energy change in a solar power plant?
light energy (sun)-> electrical energy (solar cell)
