P5 Flashcards
What is Newton’s first Law of Motion?
If the resultant force acting on an object is
zero and:
* the object is stationary, the object remains stationary
* the object is moving, the object continues to move at the
same speed and in the same direction.
What is Newton’s second Law of Motion?
The acceleration of an object is proportional
to the resultant force acting on the object, and inversely
proportional to the mass of the object.
F = ma
Resultant force= mass x acceleration
What is Newton’s third Law of Motion?
Whenever two objects interact, the forces they exert on each other
are: equal and opposite.
List the CONTACT forces
-Friction
-Tension
-Air Resistance
-Normal Contact
List the NON-CONTACT forces
-Magnetic
-Electrostatic
-Gravitational
What is the formula for Force using spring constant and extension?
F=ke
Force (N)= spring constant (N/m) x extension (m)
What is the relationship between the extension of a spring and force?
The extension of
a spring is
directly
proportional to
force until its
elastic limit.
What are the four resultant forces that can act on an object?
-Lift (upwards)
-Weight (downwards)
-Drag (backwards)
-Thrust (forwards)
What is the formula used to calculate Moments?
M= F x d
Moment (Nm)= Force (N) x distance (m)
d= perpendicular distance from the pivot to line of action of force(where force is being exerted)
How do things like levers increase the size of the turning force?
They use moments to increase the size of a turning force by using a long lever.
What do you have to remember to say when stating your answer as a moment?
Whether it is a clockwise or anticlockwise moment.
What is the principle of moments?
If an object is balanced:
Clockwise moment (CWM) about a point=Anticlockwise moment (ACM) about the same point
How do you calculate the turning forces of the masses used in the investigation for Moments?
W=mg
W(N)= mass(kg) x gravitational field strength(N/kg)
You do this calculation for both masses respectively
What is the unit of Weight?
Newtons, N
What is the unit of mass?
kilograms, kg
What is weight the result of?
Gravity
What is the gravitational field strength on Earth?
10 N/kg (ten newtons per kilogram).
What is the equation for Work?
Work= Force x displacement
What is the equation for Pressure?
Pressure(Pa)=Force(N)/Area(m^2)
P=F/A
Pa=Pascal
What is the other equation of Pressure? (pressure of a liquid)
pressure(Pa) = height of column(m) × density of the liquid (kg/m^3)× gravitational field strength (N/kg)
p=hρg
Define Upthrust
Upwards force exerted by a liquid or gas on an object floating in it.
-An object that is partly, or completely, submerged experiences a greater pressure on its bottom surface than on its top surface. This causes a resultant force upwards. This force is called upthrust.
What is the rule of Upthrust?
If the upthrust is less than the weight of the object, the object will sink. If the upthrust is larger than the weight of the object, the object will float.
Define a Moment
The turning effect of a force
What is the pivot of an object also known as?
The fulcrum
What is the conservation of Momentum?
In a closed system, the total momentum before an event is equal to the total momentum after an event.
What is the terminal velocity of an object?
When the object reaches a constant velocity
