P8 Forces in balance Flashcards
vector
quantity with size and direction- magnitude
scalar
quantity with magnitude only
newton’s third law of motion
when two objects interact with each other they exert equal and opposite forces on each other
driving force
pushes an object forward because of the friction between the ground and tyre of each drive wheel
newton’s first law of motion
if the forces acting on an object are balanced, the resultant force is 0
resultant force
equal to difference between two forces
in direction of larger force
moment + factors
turning effect of the force
increased by: increasing size of force, using spanner with longer handle
levers
weight= load
force applied= effort
point about which it turns= pivot
line of action
line that a force acts along
moment eq
force x perpendicular distance from line of action of the force to the pivot
changing gears
low gear gives low speed and high turning effect
high gear gives high speed and low turning effect
lever as force multiplier
exerts a greater force than the force applied to the lever by the effort
increase moment of turning effect
a small gear wheel needs to drive a larger gear wheel
centre of mass
point of an object at which its mass can be thought of as being concentrated
principle of moments
sum of all the clockwise moments about any point= the sum of all the anticlockwise moments about that point
