Forces Flashcards
How do you calculate speed?
Speed = Distance/Time
What is speed measured in?
Metres per seconds M/s
What is time measured in?
Secconds s
What is distance measured in?
Metres m
Scalar Quantity? And examples?
A scalar quantity only has a magnitude, size.
E.G - distance, speed, time, mass etc
Vector Quantity? And examples?
A vector quantity has both a magnitude (size) and a direction.
E.G - acceleration, velocity, force, displacement etc
If an object has a speed/velocity as a negative value what does this mean?
The object is going in reverse direction
What is distance?
How far an object has travelled
What is displacement?
How far an object is relative to its starting point
A distance-time graph can be used to measure speed of a moving object, how?
By working out the gradient,
Change in Y/Change in X = Speed
What does a steeper line mean on a distance-time graph?
The steeper the line the faster the object
What do lines that aren’t straight mean?
A speed that is changing.
What does a line below the horizontal axis represent?
An object with a negative displacement
How do you calculate acceleration?
Change in speed/Time
What is the unit for acceleration?
m/s^2 = Metres per second
How can you tell if an object is slowing down?
If its acceleration has a negative value. This is called retardation or deceleration
How can you tell if an object is at constant speed? (Speed/Time graph).
If it’s speed is represented as a level line on the graph.
What does a negative gradient mean? (Speed/Time graph).
Decleration
What does a level line following the horizontal axis mean? (S/T graph).
The object is not moving
How can you work out the distance travelled from a s/t graph?
By calculating the are underneath the curve; find the value of one square, work out how many squares there are and then times the number of square to the value of the square
If an object has an unbalanced force, what does this mean?
If an object has an unbalanced force it becomes a resultant force. So the object will accelerate - in the direction of the resultant force.
What happens if the resultant force is acting backwards?
Decelerates the object, the direction of the driving force always determines the direction of motion.
What is mass?
A measure of how much matter makes up an object. Measured in kgs.
What is weight?
Weight is the force exterted by an object (downwards) due to gravity. It is measured in newtons.
Formula for weight?
Weight = Mass X Gravitational Field strength
What is Newton’s 1st Law?
An object will remain at rest unless acted upon by an external or unbalanced force.
An object will remain in motion unless acted upon by an external or unbalanced force.
What is Newton’s 2nd Law?
The rate of change in momentum of a body is proportional to the resultant force acting on the body and is in the same direction.
What is Newton’s 3rd Law?
For an object with constant speed, the forces are always working in pairs and these two forces are equal in magnitude and opposite direction.
Every action has an opposite and equal reaction.
What heppens an object has balanced forces?
The object is travelling at a constant speed.
When does terminal velocity occur?
When an object is travelling at maximum speed, and its forces are balanced TERMINAL VELOCITY occurs.
How does terminal velocity occur?
Fast motion creates air resistance which eventually balances out the driving force.
How do you work out force?
FORCE = MASS X ACCELERATION
How do you work out velocity?
Displacement/Tim
