Topic 2) Forces Flashcards
newton’s first law
an object remains, or move with a constant velocity unless acted on by a resultant force
what does Newtons first law tell us?
how objects travel at constant velocity
what happens if forces acted on are balanced?
the resultant force is zero
how can a velocity change?
only if a resultant force acts on the object
what is the equation for resultant force?
resultant force = mass x acceleration
what does newtons third law tell us?
every action has a equal and opposite reaction
example of force pairs
the cat pulls the earth up
the earth pulls the cat down
where is the centre of mass of an object?
it depends on the objects shape, it can be inside or outside of it
what is the equation for weight?
weight = mass x gravitational field strength
what are you measuring when measuring weight?
the force pulling the object towards the centre of the earth
what is Newtons second law?
the acceleration of an object is proportional to the resultant force acting on it and inversely proportional to the object’s mass
what does Newtons 2nd law explain?
-an object will accelerate in response to a resultant force
-the bigger the resultant force, the bigger the acceleration
-for a given force, the greater the object’s mass, the smaller the acceleration experienced
example of Newtons 2nd law
the baseball experiences a large resultant force, so accelerates quickly to a home run
what is the equation for the change in velocity?
change in velocity = final velocity - initial velocity
what is the equation for acceleration?
change in velocity / time
what is the core practical for forces?
investigating force and acceleration
what is the aim of investigating the effect of forces on accelerating?
to investigate the effect of varying force on the acceleration of an object of constant mass
what is the aim of investigating the effect of mass on acceleration?
to investigate the effect of varying mass on the acceleration of an object produced by a constant force
what is the equation for speed?
speed = distance travelled / time taken
what does it mean if an object is moving in a circular motion?
it is travelling at a constant speed
where is the centripetal force if a car is travelling around a roundabout?
friction between car tyres and the road
what is the centripetal force?
the resultant perpendicular force towards the centre of the circle required to keep a body in uniform circular motion
