Forces and Motion Flashcards
What does the gradient of a distance time graph show you?
Speed (or velocity)
What does a flat line (gradient = 0) on a distance time graph show you?
No movement (staying still)
What does a steep line (high gradient) on a distance time graph show you?
High speed (fast)
What does a shallow line (low gradient) on a distance time graph show you?
Low speed (slow)
What is velocity?
The same as speed but a direction is also given
What does the gradient of a velocity time graph show you?
Acceleration
What does a flat line (gradient = 0) on a velocity time graph show you?
Steady (constant) speed
What does a steep line (high gradient) on a velocity time graph show you?
Large acceleration
What does a shallow line (low gradient) on a velocity time graph show you?
Small accceleration
What does the area under a velocity time graph show?
Distance travelled
What is the equation linking speed, distance and time?
Speed= Distance/Time
What is the equation linking acceleration, change in velocity and time?
Acceleration = change in velocity ÷ time
What is the equation linking force, mass and acceleration?
Force = mass x acceleration
What is the equation linking weight, mass and g?
Weight = mass x g
What are the units of force?
Newton (N)
What are the units of acceleration?
m/s^2
If you distance was measured in m and your time measured in s, what would your speed be measured in?
m/s
If you distance was measured in km and your time measured in hours, what would your speed be measured in?
km/h
What is the unit of weight?
N (because it is a force)
What is the unit of mass?
Kg (turn g into kg by ÷ 1000)
What do unbalanced forces do to an object?
Make it change speed, shape or direction
What is the gravitational force called?
Weight (don’t say gravity!!!!)
What will happen to an object with balanced forces on it?
Stays at same speed
What happens to an object as it falls through the air?
1) The object will have the forces of weight (don’t say gravity!!!) acting downwards and air resistance acting upwards.
2) At the start the forces are unbalanced so the object accelerates (Force = mass x acceleration)
3) As it gets faster, the air resistance increases
4) The air resistance will increase until it is the same size as the weight so the forces are balanced
5) This means the object will stop accelerating and fall at a constant speed called terminal velocity.
What is Hooke’s Law?
Force is proportional to extension (up to the elastic limit)
What does a material that obeys Hooke’s Law look like on a force-extension graph?
A straight line (through the origin)
What is an elastic material?
A material that goes back to its original shape after the deforming force has been removed.
