Unit 3 : Forces and Energy Flashcards
(25 cards)
What is a force?
A push or pull that can change the speed, direction, or shape of an object.
What is the unit of force?
Newton (N)
Name three effects a force can have on an object.
It can change the object’s speed, direction, or shape.
What tool is used to measure force?
A Newton meter (spring scale).
What is the formula for speed?
Speed = Distance ÷ Time
(S = D / T)
What are the units for speed, distance, and time?
Speed: m/s or km/h
Distance: meters (m) or kilometers (km)
Time: seconds (s) or hours (h)
If a car travels 100 km in 2 hours, what is its speed?
50 km/h
What does a flat line on a distance-time graph mean?
The object is stationary (not moving).
What does a steep line on a distance-time graph represent?
The object is moving quickly (higher speed).
How can you tell if speed is changing on a graph?
If the line is curved, speed is changing (acceleration or deceleration).
What is a turning force called?
A moment.
What is the formula for calculating a moment?
Moment = Force × Distance from pivot
What are the units of a moment?
Newton-metres (Nm)
What is the pivot?
The fixed point that an object rotates around.
What is the formula for pressure?
Pressure = Force ÷ Area
What is the unit of pressure?
Pascals (Pa) or N/m²
How does reducing the contact area affect pressure?
It increases pressure.
Why do sharp knives cut better than blunt ones?
Because they have a smaller surface area, increasing the pressure.
How does pressure in a liquid change with depth?
It increases as depth increases.
Why do divers feel more pressure the deeper they go?
Because there’s more water above them, increasing the weight and pressure.
How do gases create pressure?
By their particles colliding with the walls of their container.
What happens to gas pressure when temperature increases?
Pressure increases because particles move faster and hit the walls more often.
How are particles arranged in a solid, liquid, and gas?
Solid: tightly packed, fixed positions
Liquid: close together, but can move past each other
Gas: far apart and move freely
What is diffusion?
The spreading out of particles from an area of high concentration to low concentration.
