P5: NEWTON'S LAWS OF MOTION Flashcards
Newton’s 1st law
an object at rest will stay at rest and an object in motion will move at a constant velocity unless acted on by an unbalanced force
What is centripetal force?
resultant force that causes the change in direction and acts towards the centre of the circle
Why does an object moving in a circular motion have a constant speed but a changing velocity?
-velocity is a vector quantity meaning it has magnitude and direction
-change in direction = change in velocity
How does the speed of an object affect drag?
the faster an object is travelling, the larger the drag force will be
What is terminal velocity?
when a falling object reaches a constant speed
How does an object reach terminal velocity?
-at the start, the object accelerates downwards due to the force of gravity
-as the object’s speed increases, drag increases
-at terminal velocity, the weight of the object due to gravity is balanced by the drag force, and the resultant force is zero
What is Newton’s 2nd law?
acceleration of an object is directly proportional to the resultant force exerted on it and inversely proportional to its mass
What is the equation for Newton’s 2nd law?
force (N) = mass (kg) x acceleration (m/s^2) (F=ma)
What is inertia?
the tendency for motion of an object to remain unchanged
How does mass affect inertia?
the greater the mass the greater the inertia
What does inertial mass measure?
how difficult it is to change the velocity of an object
What is Newton’s 3rd law?
when object A exerts a force on object B, object B will exert a force which is equal and opposite on object A (the forces must be: the same type, the same size, in opposite directions and and acting on 2 separate objects)
