FORCES Flashcards
(22 cards)
What is a scalar quantity?
- just a number
- distance
- mass
- speed
What is a vector quantity?
- number and a direction
- displacement
- weight
- velocity
- acceleration
- force
- momentum
Equation for distance
s = v x t
distance (m) = speed or velocity (m/s) x time (s)
What does a straight line mean on a distance-time graph?
Object is not moving
What does a steep line mean on a distance-time graph?
The object is going fast
The steeper the line, the faster the object
How do you know if an object is moving on a distance-time graph?
The line will be moving upwards ↗️
How do you find the speed on a distance-time graph?
Speed = gradient
= up ÷ across
= distance ÷ time
What does a straight line mean on a velocity-time graph?
The object is moving at a steady speed
What does a curved line mean on a velocity-time graph?
The object is accelerating
How do you find the acceleration on a velocity-time graph?
Acceleration = gradient
= velocity ÷ time
= up ÷ across
How do you find the distance travelled on a velocity-time graph?
Area under graph
Triangle = 1/2 x b x h Rectangle = b x h
Equation for acceleration
a = v-u
——
t
acceleration (m/s²) = final velocity (m/s) - initial velocity (m/s) ÷ time taken (s)
What is V² - u² equal to?
final velocity - initial velocity
m/s
2 x a x s
2 x acceleration (m/s²) x distance (m(
What is the value of gravity on Earth?
10N/kg
What is the value of gravity if you are falling on Earth?
10m/s²
What do you need to find when looking for a resultant force (N)?
The difference (subtraction)
What does it mean if an obects resultant force is 0N?
The object has no movement
Equation for force
F = m x a
Force (N) = mass (kg) x acceleration (m/s²)
Equation for weight
W = m x g
weight (N) = mass (kg) x gravity (N/kg)
Mass and weight facts
- Mass never changes
- Weight depends on gravity
- Changes on other planets
What is centripetal force?
The resultant force when things are moving in a circle
Constant speed, changing direction
Want to move straight but is forced to go circular
Equation for momentum
P = m x v
momentum (kg m/s) = m (kg) x v (m/s)
