P1.5 - Forces Flashcards
What can forces produce change in on an object? [3]
- size
- shape
- motion
What is friction? [3]
- the force between two surfaces that may prevent relative motion and produce heating
What mediums does friction act along? [2]
- liquid
- gas
When does friction act? [2]
when an object is moving through a liquid or gas
What’s an example of friction acting against a gas? [1]
air resistance
What are forces measured in? [1]
newtons (N)
What is a force? [2]
the pull or push of an object that attempts to change it’s motion, shape or size
What are examples of forces: [4]
- physically pushing or pulling an object
- magnets pushing or pulling
- electric charges pushing and pulling
- gravitational forces pulling objects together
When are magnitudes of forces added together? [1]
when forces are going in the same direction
What does it mean if the acceleration is 0? [4]
- means speed is not changing
- DOES NOT MEAN IT’S STAYING THE SAME
- it is travelling at the same speed
- neither accelerating nor deccelerating
Which things are in the same direction? [2]
the resultant force and the acceleration
What is the spring constant? [1]
force per unit extension
What is terminal speed/velocity? [1]
when acceleration is equal to 0 and the object begin to fall down at a constant speed
What happens if the total force applied to an object is 0? [1]
object won’t change it’s motion and is equilibrium
What is the description of moment of a force? [2]
the turning effect brought on a body due to application of force
What is moment of a force? [2]
the product of the force and perpendicular distance from pivot to line of action of the force
What is the formula for moment of a force? [2]
moment = force x perpendicular distance from the pivot
What is the unit for the moment of a force? [1]
newton metre (n.m)
When is an object in equilibrium? [1]
when there is no resultant force and no resultant moment
Which ways can a moment rotate? [2]
clockwise and anti-clockwise
If the moment is anti-clockwise, what do you use? [1]
+
If the moment is clockwise, what do you use? [1]
-
What is the principle of moments? [3]
if a body is not to rotate, the net clockwise moment on it must equal the net anti-clockwise moment
What is the centre of gravity? [2]
it is the point on a body where the whole of the weight is assumed to be acting
If the base area of an object is thicker/bigger, what happens to the stability? [1]
it is more stable and better stability
How does distance from the ground affect stability? [2]
the closer the centre of gravity is to the ground the more stable the object is
What is the limit of proportionality? [2]
the load after which the extension will not increase linearly with the load
