P2 - Forces and Motion Flashcards
(22 cards)
What is a resultant force?
the overall force or the result of two or more forces acting on an object
What type of quantity is a force?
vector quantity
What does the length of an arrow on a free body diagram show?
the size of the force
What force acts downwards on all objects?
weight (gravity)
What does it mean if an object is in equilibrium?
forces are balanced
Give the two ways an object will be moving if the forces acting upon it are balanced
object will be either:
- stationary
- moving at a constant velocity
Give the two ways an object will be moving if the forces acting upon it are unbalanced
object will be either:
- accelerating
- decelerating
What do unbalanced forces cause?
a change in velocity
Do balanced forces change the velocity of an object?
no
What does a changing velocity mean there is?
an unbalanced force
What is required to change the motion of an object (think Newton’s first law)
a resultant force
Define centripetal force
forces moving around a centre point
What are all objects moving in a circle doing?
continuously accelerating towards the centre of the circle
When an object moves in a circle, what is the acceleration doing?
changing the direction of motion, but not the speed (speed is continuous)
According to Newton’s first law, what is a moving object with a resultant force of zero doing?
moving at the same velocity
According to Newton’s first law, what is a stationary object with a resultant force of zero doing?
remaining stationary
What is the equation used in Newton’s second law?
force = mass x acceleration
f = m x a
What is Newton’s second law?
if a non- zero resultant force acts on an object, then it will cause the object to accelerate
what will happen if a non-zero resultant force acts on an object?
it will accelerate
what is the resultant force directly proportional to?
the acceleration it causes
what are the two equations for acceleration?
a = v-u/t
a= v²=u²+2ax
