P8(Forces In Balance) Flashcards
What is displacement
a measure of how far something is from its starting position, along with its direction
What is a vector
A physical quantity which has magnitude and direction
What is a scalar
A quantity that has magnitude but no direction
How can a vector quantity be represented
By an arrow in the direction of the vector and of length in proportion to the magnitude of the vector
What is newton’s 3rd law
When 2 objects interact they always exert equal and opposite forces on each other
Forces can …
-Change the shape of an object
-Change an objects motion
-Change the objects state of rest
What is a contact force
A force that acts on objects only when the objects touch each other
What is newtons 1st law of motion
If the forces acting on an object are balanced, the resultant force on the object is zero
What is the resultant force
A single force that has the same effect as all the forces acting on an object
If the resultant force on an object is:
-Zero, the object stays at rest or at the same speed and direction
-greater than zero, the speed or direction of the object will change
If an object is acted on by 2 unequal forces acting in opposite directions the resultant force is:
-equal to the difference between the 2 forces
-in the direction of the larger force
If 2 forces act on an object along the same line the resultant force is:
-their sum, if the forces act in the same direction
-their difference, if the forces act in opposite directions
What is a moment
A measure of the turning effect of the force on an object
The moment(turning effect of the force) can be increased by:
-increasing the size of the force
-using a spanner with a longer handle
Levers can be used to …
Exert a force that is greater than the effort
What is the formula for moments
What’s the formula to calculate the force needed to stop an object turning
