Ch 9 - Application of Forces and Transfer of Energy Flashcards
Destructive forces in nature can cause…
- Loss of lives and livelihood
- Serious damage to infrastructure, buildings and environment
- Erosion of coastlines and landslides
Examples of how forces affect nature??
qn marks cus idk if this make sense
- volcanic eruption
- earthquake
- tsunami
- cyclone
What is a force?
It is a push or a pull.
What are contact forces? 👏
It is a force that acts on objects when they physically come in contact with one another.
Examples of contact forces.
- friction
- elastic force
- air resistance
- water resistance
What is friction?
It is a contact force that acts on two materials rubbing against each otherI
Real-life situations of friction
- When writing with a pencil✏️, friction transfers carbon lead onto paper
- When striking a matchstick, friction causes heat allowing the head to catch fire 🔥
Friction ____ motion - it ____ moving objects.
Friction opposes motion - it slows down moving objects.
Friction acts in (which direction?)
the opposite direction of motion
Useful effects of friction 👍
- Chalk powder for gymnasts 🤸 : too absorb sweat, improving their grip to stop them slipping from the apparatus
- Daily activities (walking, holding objects) : to provide grip
Undesirable effects of friction 👎
- produces heat
- the heat leads to wear and tear of the material after some time
How to reduce friction?
Use lubricants; ball bearings; rollers; cushion of air etc.
What is elastic force?
It is the force acting on a stretched or compressed object to return to its original shape.
What is water/air resistance?
it is when an object moves through air/any other fluid –> the fluid exerts a friction-like force on the moving object.
What are non-contact forces? 👏
A force that acts on an object without coming physically in contact with it.
Examples of non-contact forces
- Magnetic force 🧲
- Gravitational force ☁️
What is magnetic force? 🧲
It is the force exerted by a magnet on magnetic materials such as iron & steel.
A magnet has…
a north pole and a south pole
BRRR..SO COLD 🥶
Real-life situation of magnetic force
Maglev trains!! 🚅
They stay above the tracks by repelling the magnets on the track, allowing them to travel faster in the absence of friction.
What is gravitational force? ☁️
It is the force of attraction between masses.
Gravitational force affects…
ALL OBJECTS THAT HAVE MASS !!
An object of larger mass produces a ____ gravitational force on an object of smaller mass.
😃 LARGER 😃
What is weight?
amount of gravitational force exerted on body
S.I. unit of force
newton (N)
symbol of force
N(my name) 🤣
A force meter is…
an instrument used to measure forces (e.g. spring balance)
What is the formula for weight?
W = mg
Explain { W = mg }
W - weight of the object (N)
m - mass of the object (kg)
g - gravitational field strength (N/kg)
What is mass?
Amount of matter in body
S.I. unit of mass
kilograms (kg)
Does mass change depending on location?
NOPEE, it stays constant regardless of location
Does weight change depending on location?
YESS, it varies
How is mass measured?
beam balance or electronic balance
How is weight measured?
extension spring balance or compression spring balance
A force can…
