P8 - Forces In Balance 2️⃣✅ Flashcards
What is a scalar quantity?
A scalar quantity only has magnitude (size)
What is a vector quantity?
A vector quantity has magnitude (size) and direciton
What is displacement?
Distance in a given direction
What is Newtons 3rd Law?
When an objects interact, they always exert equal and opposite forces on eachother
What is a contact force?
A force where the objects are physically touching
What is a non-contact force?
A force where the objects are physically separated
What is Newtons 1st Law?
An object will remain at a constant velocity unless a resultant force acts upon it
What is a resultant force?
A single force equivilent to all the forces acting on an object
Give 5 examples of a contact force
- fricton
- air resistance (drag)
- tension
- normal contact forces
- upthrust
Give 3 examples of a non-contact force
- gravity
- magnetic force
- electrostatic
The weight of an objects depends on what?
The gravitational field strength at the point where that object is
What is a moment?
A moment is the turning effect of a force
What is the pivot?
The centre of rotation
What is another name for a pivot?
A fulcrum
What is the principle of moments?
If an object is at equilibrim, the sum of all the clockwise moments about any point = the sum of all the anticlockwise moments about that point
What is the equation for moments?
moment of force (Nm) = force (N) x PERPENDICULAR distance from pivot (m)
What is a lever?
A mechanism that uses moments to make a job easier. Its a force multiplier, meaning it requires less force than it delivers
What is a gear?
A rotating wheel with ‘teeth’ (cogs) used to transmit power
What is a free-body force diagram?
A diagram that shows the forces acting on an object
What is the centre of mass?
The center of mass is the point where we can assume all the mass of the object is concentrated
Where can you find an objects centre of mass if its a regular shape.
Where all of its lines of symmetry cross
