P10 forces and motion Flashcards
what is acceleration?
the change in velocity over a given time
what is decceleration?
when an object slows down (negative acceleration)
how do you calculate acceleration from a VELOCITY time graph?
the gradient of the graph
what is the initial acceleration of an object falling to the earth?
approximately 9.8m/s2
what is the acceleration of a falling object due to?
the force of gravity acting on the object
what do air particles cause on a falling object?
an upward force of friction to act on the object called air resistance
what is terminal velocity?
when the force of air resistance balances the force of gravity so the object stops accelerating and reaches a constant velocity
where does terminal velocity apply?
to any falling object through a fluid
what affects the terminal velocity of an object?
the shape of the object affects the amount of air resistance on the object. this affects the terminal velocity
what is Newton’s first law of motion?
if the resultant force of a stationary object is 0, it will remain stationary
if the resultant force of a moving object is 0, the object will continue to move with the same velocity
what is Newton’s second law of motion?
the acceleration of an object is proportional to the resultant force acting on the object and inversely proportional to the mass of the object
aka - F=ma
what are the typical speeds of a car on the motorway and a normal road?
approx. 13 m/s on a typical road
approx. 30 m/s on a motorway
what is the typical acceleration of a car travelling from a road to a motorway?
2 m/s2
what is another way of describing Newton’s first law?
objects will stay still or continue to move with constant motion unless you apply a resultant force
what is inertia?
the tendency for an object to stay at rest or continue in uniform motion (due to Newton’s 1st law)
what is inertial mass?
a measure of the difficulty of changing an object’s velocity
what is Newton’s third law of motion?
whenever two objects interact, they exert equal and opposite forces on each other
what do all moving objects have?
momentum