Topic 5 - Forces (paper 2) Flashcards
What is a moment?
rotational or turning effect of a force
What is the formula for a “moment”?
M = Fd
What is the unit for a “moment”
Newton metres (Nm)
What is the “d” in the equation for “moments”
perpendicular distance
In a balanced seesaw the total clockwise moment is …….. to the total anti- clockwise moment. Fill in the gap.
Equal to
How do levers work?
They work by transmitting the turning effect of a force
What is the formula for weight?
Weight = mass x gravitational field strength
W = mg
When two gears are connected, do the gears turn in opposite directions, or the same directions?
Opposite directions
What is the relationship between the ratio of the turning effect of the two gears to the ratio of the radius of the two gears
They are proportional
True or False? All states exert pressure.
True
What states does the term “fluid” refer to?
Liquid or Gas
What is the formula for pressure?
Pressure = force/ area
P = F/A
What’s the unit for pressure?
Pascals (Pa)
What are the factors which determined the pressure exerted by a liquid?
The depth, density of liquid, gravitational field strength
What is the formula for pressure in a liquid?
p = hpg
What’s the units of pressure in a liquid?
Pascals (Pa)
What It is upthrust caused by?
The pressure on the bottom of the object being greater than the pressure on the top of the object
What will happen to an object if it is more dense than the liquid its in?
It will sink
Is atmospheric pressure higher or lower at a higher elevation?
Lower
What does atmospheric pressure refer to
the total force of all the air particles constantly colliding with everything, from all sides
Why is there a greater atmospheric pressure at sea level than at a higher elevation?
There are more gas particles at sea level to collide with objects and the air is more dense at sea level
What are the two main gases which make up the atmosphere?
Nitrogen and Oxygen
What is a scalar quantity?
Only has magnitude
What is a vector quantity?
Has both direction and magnitude
Is speed a scalar or vector quantity?
Scalar quantity
Is velocity a scalar or vector quantity?
Vector quantity
Is distance a scalar or vector quantity?
Vector quantity
Is displacement a scalar or vector quantity?
Scalar quantity
What is the formula for velocity?
velocity = speed/ time
v = s/t
What is acceleration?
The rate of change of velocity
What is the formula for acceleration?
acceleration = change in velocity/ time
What is another formula for acceleration?
v^2 - u^2 = 2as
final velocity^2 - initial velocity^2 = 2 x acceleration x distance
On a distance/ time graph what axis is distance on?
y-axis
On a distance/ time graph what axis is time on?
x-axis
What does the gradient of a distance/time graph tell us?
the speed of the object
What does a flat line on a distance/time graph tell us?
The object is stationary
How to find the velocity at a point on a distance/time graph?
Draw a tangent at the point and use it to find the gradient of the line
On a velocityy/ time graph what axis is velocity on?
y-axis
On a velocity/ time graph what axis is time on?
x-axis
What does a flat line on a velocity/time graph tell us?
The object is moving at a constant velocity
What does the gradient of a velocity/time graph tell us?
The acceleration or deceleration of the object?
How can you tell the distance traveled on a velocity/time graph?
The area under the curve
What is the force that causes an object to fall towards the earth?
Weight
What is the size of the air resistance dependent on?
surface area and velocity
As the velocity of a falling object increases, the air resistance……. Fill in the gap.
Increases
What is “terminal velocity”
When an object is falling with a constant velocity
When is terminal velocity reached?
The resultant force is zero and the weight has the same magnitude as the air resistance
