Forces Flashcards
What’s a force
It’s a vector quantity that has size and directions
What’s a force measured in
Newtons (N)
What’s a force represented by in a diagram
An arrow
What’s a balanced force
When there is no resultant force, they do not change velocity of an object
Balanced forces are summer up in ..
Newton’s first law
What’s an unbalanced force
When a resultant force causes acceleration. It will change the velocity of an object
It can make an object slow down, speed up or change direction
Unbalanced forces are summed up as…
Newton’s second law
What’s mass
Shows the amount of matter in an object
Measured in kg
What’s newton’s second laws equation
Force= mass × acceleration
What’s friction
A force which always opposes motion
What’s weight
The force of gravity on an object
What’s acceleration of free fall
The acceleration of an object towards the surface of the earth when the only force on it is the gravitational force
Weight is the force of gravity in an object. Since objects close to the earth all experience the same acceleration, we can apply newton’s second law.. what’s the equation
Weight=Mass × acceleration due to gravity
W= m×g
What’s gravitational field strength,g
The gravitational force on an object of mass 1kg close to the surface of earth
What’s the earth’s gravitational field strength
10N/kg
What’s the moons surface value of g
1.6N/kg
G also gives gravitational acceleration
What equation can be used
Acceleration=force÷mass
Or
g=weight÷mass
G can be measured in m/s²
What’s hookes law equation
F=ke
In the hookes law equation what does each letter stand for
F=
k=
e=
F=force(N)
k=spring constant(N/cm or N/mm)
e= extension(cm or mm)
What’s pressure
The force per unit area on a surface
What’s pascal
The SI unit of pressure and is the same as 1N/m²
What is the equation for pressure
Force÷area
Who renamed N/m² to pascal(pa)
French scientist
What’s centre of gravity
The point through which the entire weight of a body appears to act
What equilibrium
A state in which opposing forces or moments are balanced
What’s neutral equilibrium
When slight displacement causes an object not to move away from it’s orginial position nor return to it
What’s unstable equilibrium
When displacement causes the object to move a long way from it’s orginal position
What’s stable equilibrium
When displacement causes the object to return to its orginal position
What’s a moment
Is the product of a force and it’s perpendicular distance from the point
What direction so moments go
Clockwise or anticlockwise
What’s the equation for moment
Force × distance to pivot
What does the principle of moments state
A lever is balanced, the sum of the clockwise moments about any point equals the sum of the anticlockwise moments about the same point
