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.
