Important Equations Flashcards
What is mass?
A measure of the amount of (matter) substance in an object. In grams or kilograms.
What is weight?
The force of gravity acting on an object.
What is friction?
A force which opposes motion.
What is density?
The mass of 1 cm³ of the material.
What does Hooke’s Law state?
The extension of a spring is directly proportional to the applied load provided the limit of proportionality is not exceeded.
Define pressure?
The force of an object divided by the area of the object in contact with a surface.
P=f/a
What is the centre of gravity?
The point on an object where weight appears to act.
What is the centre of mass?
The point on an object where all the mass appears to be concentrated.
What is a moment?
The product of the force and the perpendicular distance from the pivot to the line of action of the force.
What is the principle of moments?
When an object is in equilibrium, the sum of the anticlockwise moments equals the sum of the clockwise moments (ACM=CM) about the same point.
Fill in the blank: Weight = _______ X gravity.
[mass]
Fill in the blank: Density = _______ ÷ volume.
[mass]
Fill in the blank: Force = _______ X extension.
[spring constant]
Fill in the blank: Pressure = _______ ÷ area.
[force]
Fill in the blank: Moment = _______ X perpendicular distance from pivot.
[force]
True or False: Anticlockwise moments equal Clockwise moments in equilibrium.
True
What is a scalar quantity?
A scalar quantity has magnitude only.
Examples include temperature and mass.
What is a vector quantity?
A vector quantity has both magnitude and direction.
Examples include velocity and force.
Define acceleration?
The rate of change of velocity.
What does resultant force refer to?
Unbalanced force.
State Newton’s First Law of Motion.
An object stays at rest or continues to move in a straight line with constant speed, unless acted on by a resultant force.
What is air resistance?
A friction force acting in the opposite direction to the movement of the object.
What is the acceleration of free fall?
An object falling freely from rest will accelerate at 10m/s² due to gravity.
What is terminal velocity?
The constant velocity reached by a falling object when magnitude of the air resistance force is equal to the magnitude of the weight of the object.
State Newton’s Second Law of Motion.
The force applied to an object is equal to the mass multiplied by the acceleration.
Fill in the blank: Speed = _______ ÷ time.
distance
Fill in the blank: Velocity = _______ ÷ time.
displacement
What is the formula for average speed?
Average speed = initial speed + final speed/2
Or
S= d/t
What is the formula for average velocity?
Average velocity = Total displacement ÷ Total time.
What is the formula for rate of change of speed?
Rate of change of speed = (final speed - initial speed) ÷ time (V-U/T)
What is the formula for acceleration?
Acceleration = final velocity - initial velocity / t
What is the formula for resultant force?
Resultant force = mass X acceleration
What does the gradient of a distance-time graph represent?
Speed
What does the area under a velocity-time graph represent?
Displacement
What is the relationship between velocity and time in a velocity-time graph?
Acceleration
What does the gradient of a velocity-time graph indicate?
Rate of change of speed
Fill in the blank: Speed is represented on a _______ graph.
Speed - Time
True or False: The area under a distance-time graph represents acceleration.
False
Newtons 3rd Law
When objects interact with each other, they always have an equal and opposite reaction
