Forces Flashcards
What is a force?
A force is something that can change the shape, size, motion, or direction of an object, and it can cause a turning effect or increase/decrease pressure. A force is a push or pull acting on an object. It is measured by a spring balance or dynamometer It
A push or pull acting on an object.
What is the unit of force?
Newton (N)
How do mass and weight differ?
Mass is the amount of substance in an object and is constant, measured in kg. Weight is the force due to gravity on an object, changes with gravity, measured in newtons (N), calculated using W=m x g.
An object with greater mass will have greater weight.
What is pressure?
Pressure is the force exerted per unit area, with the SI unit being Pascal (Pa) or N/m².
Formula: p = force/Area.
What is the formula for pressure due to liquid?
p = density x gravity x height of liquid (dgh)
What happens to atmospheric pressure as altitude increases?
Atmospheric pressure decreases as altitude increases due to lower air density which decreases the amount of air particles. Hence, there is lesser air particles to push down on us.
What is work in physics?
Work is done when a force causes an object to move in the direction of the force. It is measured in Joules (J), with the formula Work (J) = Force (N) x Distance (m).
Conditions for work: a force must be applied and the object must move in the same direction as the force.
What does it mean when energy is conserved?
Energy is conserved when the total energy remains constant, meaning it is transferred from one object to another or converted from one form to another.
What are some sources of energy we use?
- Fossil fuels
- Solar energy
- Hydroelectric energy
- Wind energy
- Geothermal energy
- Biofuels
- Nuclear energy
What are fossil fuels?
Fossil fuels are formed from the remains of dead plants and animals buried for millions of years, and they release heat energy when burned.
They are limited and will eventually run out.
What is the impact of using fossil fuels?
Burning fossil fuels releases air pollutants and greenhouse gases, contributing to global warming and climate change.
How is solar energy harnessed?
Solar panels convert sunlight into electrical energy.
Energy conversion: light energy (from sun) → electrical energy (solar cell).
What is hydroelectric energy?
Hydroelectric energy is generated by turbines powered by moving water, typically from a dam.
Energy conversion: gravitational potential energy (water) → kinetic energy (moving water) → kinetic energy (turbines) → electrical energy (generator).
What are the advantages of hydroelectric energy?
Produces very little greenhouse gases.
What are the disadvantages of hydroelectric energy?
Reservoirs can flood areas, causing ecological disruption and displacing communities.
How does wind energy work?
Wind turbines convert wind energy into electrical energy by rotating blades connected to a generator.
Energy conversion: kinetic energy (wind) → kinetic energy (turbine) → electrical energy (generator).
What are the disadvantages of wind energy?
Requires large land areas, can harm wildlife, and produces noise pollution.
What is geothermal energy?
Geothermal energy is heat generated within the Earth that can be harnessed to generate electrical energy by using steam to power turbines.
Energy conversion: heat energy (earth’s core) → kinetic energy (steam) → kinetic energy (turbine) → electrical energy (generator).
What are the disadvantages of geothermal energy?
Requires land clearing, can harm wildlife habitats, and may release toxic elements.
What are biofuels?
Biofuels are made from plant materials, animal waste, or recycled food waste and can power vehicles.
Energy conversion: chemical potential energy (biofuels) → heat energy (vehicle engine) → electrical energy (vehicle).
What are the advantages of biofuels?
- Can be produced quickly
- Help reuse and reduce waste
- Balance carbon dioxide levels in the environment
What is nuclear energy?
Nuclear energy is harnessed from the nucleus of an atom through nuclear reactions to generate electrical energy.
Energy conversion: nuclear energy (atoms) → heat energy (nuclear reaction) → kinetic energy (turbine) → electrical energy (generator).
What are the disadvantages of nuclear energy?
- Potential health risks to nearby communities
- Risk of leakages when disposing of nuclear waste
- Possibility of accidents
What causes a tropical cyclone?
Warm oceans provide energy for powerful storms, resulting in heavy rains and strong winds.
What is a contact force?
A force acting between two objects that are in physical contact, such as friction and elastic force.
What is a non-contact force?
A force acting between two objects that are not in physical contact, such as gravitational and magnetic forces.
What is friction?
A contact force that opposes motion between two surfaces in contact.
What are the advantages of friction?
- Improved grip
- Slowing or stopping objects
- Prevents slipping and sliding
What are the disadvantages of friction?
- Wear and tear on objects
- Energy wastage
How can friction be reduced?
- Lubricating oils or grease
- Using ball bearings, rollers, or wheels
- A cushion of air
What is elastic force?
A contact force that acts when an object is stretched or compressed, opposing the applied force to restore the object to its original shape.
What is gravitational force?
An attractive force exerted between objects with mass, acting at a distance.
What is gravitational field strength?
The gravitational force exerted per 1kg, expressed in newtons per kilogram (N/kg).
What is magnetic force?
A non-contact force exerted between magnets or between a magnet and magnetic materials, involving attraction or repulsion.
What is the effect of like and unlike poles on magnets?
- Like poles repel
- Unlike poles attract
What affects gravitational field strength?
The mass of the object and the distance from the center
As the distance from the center increases, gravitational force decreases.
What is magnetic force?
Force exerted between magnets or between a magnet and magnetic substances
Magnetic force is a non-contact force.
What are the two types of magnetic forces?
- Force of attraction on a magnet or magnetic material
- Force of repulsion on another magnet
How do magnets interact with each other?
Through their north and south poles
Like poles repel, while unlike poles attract.
What is the function of Maglev trains?
They use powerful magnets to create forces of repulsion to lift the train above the track
This decreases friction and enables smoother travel.
What does a compass use to indicate direction?
A magnetic needle
This helps navigate through forests and oceans.
