Forces Flashcards
(51 cards)
What is the equation for average speed?
Distance travelled/time taken
What is the equation for acceleration?
(Final velocity-initial velocity)/time taken
What is the difference between distance and displacement?
Displacement- distance in a given direction, it’s a vector (magnitude+ direction)
Distance- scalar, only magnitude
How do you determine acceleration from a velocity time graph?
The gradient
How do you determine distance travelled from the are on a velocity time graph?
Area under the line
What is the difference between speed and velocity?
Velocity is a speed in a certain direction, it’s a vector
Speed is a scalar
What is the differences between vectors and scalars?
Vectors have both magnitude and direction (velocity, force, displacement)
Scalars only have magnitude (speed, mass)
What is negative acceleration?
Deceleration
What is the equation for average velocity?
Average velocity= displacement/time
Or
(final velocity+ initial velocity)/2
What is the equation for displacement?
(final velocity + initial velocity)/2 x time
What is the equation linking final velocity, initial velocity, acceleration and displacement
V2=u2 + 2as
What are the two types of forces?
Contact and non-contact
Examples of contact forces
Friction
Air resistance
Water resistance
Tension
Driving force
Examples of non-contact forces
Weight
Gravitational force
Electrostatic force
What can forces so to an object?
Change speed
Change direction
Change shape
What is the vector nature of forces?
Forces are vector quantities, this means that when two forces act we need to take into account the direction of these forces to find the overall net force, which is the resultant force
Calculate the resultant force of 5N are acting to the right, and 2N are acting to the left
Resultant force= 3N to the right
How do you calculate a resultant force when 2 forces are acting perpendicular?
Resultant force= force one2+ force two2 all square rooted
(Pythagoras)
What is Newtons first law of motion?
An object will remain at rest or will move with constant velocity unless an external force acts on it
What does the first law of motion means for an object at rest?
book on a table
-resultant force is 0 as the gravitational force going down, is equal to the reaction force going up
What does the first law of motion means for an object moving at constant velocity?
Car driving
air resistance=driving force
resultant force=0N
Car continues to travel at constant velocity
What is friction?
It’s a force that always acts in the opposite direction to motion
What are the factors affecting friction?
- Type of surface (roughness)
- Mass/weight
What is the equation for weight?
Weight=mass x g (10 on earth)