P8 Forces in balance Flashcards
What is a vector?
A physical quantity with a direction.
What is a scalar?
A physical quantity that has size but no specific direction.
What is magnitude?
The size of quantity.
What is Newton’s third law of motion?
When two objects interact with each other they exert equal and opposite forces on eachother.
What is a resultant force?
A single force that has the same effect as all the forces acting on an object.
What is a free body force diagram?
It shows the forces acting on an object. You put them in order then draw a line start to finish. Measure it to see how long it is.
What is a moment?
The measure of the turning effect of the force on an object.
What is the formula for a moment?
Moment(Newton meters)=force(Newtons)x perpendicular distance from the line of action of the force to the pivot, d(metres)
What is the weight of the object called?
The load.
What is the force applied called?
The effort.
What is a force multiplier?
When the effort moves a bigger load such as a lever.
Why are gears used?
To change the moment of a turning effect.
What is the centre of mass?
The point where its mass is concentrated.
What is suspended equilibrium
If you suspend an object and then release it, it will come back to rest, with the centre of mass below the point of suspension. It is then in equilibrium and there is no turning effect due to the mass being at equilibrium. If it is turned then it will return to the equilibrium.
What is the principle of moments?
The sum of all the clockwise moments about any point=the sum of all the anticlockwise moments about any points
What is the parallelogram of forces?
Where if two vectors produce equal resultant forces and have the same angle, this geometrical method is called the parallelogram of forces.
What are the conditions required for something to be at equilibrium?
The resultant forces being zero and having no turning effect.
What is Newtons 1st law of motion?
All objects remain in the same state of movement unless a force is acted upon it.
What is Newtons 2nd law of motion?
Force on an object=mass x acceleration
Why are levers used?
To transmit the turning effect of a force.
