Forces Flashcards
What is a force?
A force is something that acts in an object that can change its shape, dried film or speed.
What is force measured in?
Newtons (N)
What type of quantity is force?
A vector quantity
What are the three main force types?
Push
Pull
Twist
What are friction and air resistance in comparison to each other?
Opposing forces
What happens when two solids are rubbed together?
Friction opposes movement
What happens when an object moves through air?
Air resistance opposes movements
Where does thrust come from?
Thrust comes from engines or pushing forces
What force stops us from falling through the earth?
Normal force pushing up from the ground
How do you draw a full body diagram?
Draw a circle or square as the object
Draw arrows in the direction of the forces
What is left over force called?
A resultant force
What does it mean if there is resultant force?
The forces are unbalanced
What do we call gravity?
Force due to gravity
What is normal force?
The force when an object is on the ground
What is Newton’s first law?
If there is no resultant force then a body remains moving at a constant velocity or it remains at rest
If there is a resultant force then a body will speed up, slow down or change direction –> accelerate
If forces in opposite directions are equal what does it mean?
The forces are balanced, the resultant force is zero
What does it mean if forces on an object are unbalanced?
There is a nonzero resultant force on the object
What can happen to the force if an object is moving?
The force can change the speed or direction of movement.
If an object moves in a circle what does this mean about its speed and what does it mean about its velocity?
It has a constant speed but a changing velocity
For a change in direction to happen in an object what must there be?
Ethereal needs to be a resultant force
What do we call the force that allows an object moving in a circle to move?
The centripetal force
Where does the centripetal force act?
Towards the centre of a circle
What three things can the centripetal force be caused by?
Tension, friction or force due to gravity
What is gravitational field strength a fancy word for?
Gravity
What are the two ways to change weight?
Change the mass
Change the amount of gravity acting upon the object
What is mass?
Mass is how much matter we are made of. It is also the measure of how difficult it is to change the velocity of an object.
What is weight?
Weight is a force and if is a measure of how much a planets gravity is pulling on us?
What quantity is mass?
A scalar quantity.
What quantity is weight?
A scalar quantity
What is the equation to work out weight?
Weight = mass x gravitational field strength
What is the SI to measure mass?
Kg
Why do we measure gravitational field strength in?
M/s^2
What is the gravitational field strength on earth?
10m/s
What do force and mass effect on objects?
The acceleration of objects?
What is Newton’s second law?
Acceleration is; directly proportional to the resultant force. Inversely proportional to the mass.
What is the equation to work out force?
Force = mass x acceleration
What do we measure acceleration in?
m/s^2
What do we have to call mass?
Inertial mass
What is an easy way to work out weight on earth?
Weight on earth is mass x 10
How do you work out the distance using a velocity time graph?
Base x height
Speed = ?
Speed - distance / time
What is the SI unit for speed?
Meters per second
What is the SI unit for distance?
Meters
What is the SI unit for time?
Seconds
Weight = ?
Weight = mass x gravity
V^2 - u^2 = ?
2 x a x X
Why is velocity?
Speed in a given direction
What is acceleration at constant velocity?
0 m/s
When does velocity change?
Velocity changes when an object changes direction
What direction does centripetal force act in?
Inwards towards the object
What does centripetal force cause an object to do?
Constantly change direction
What is drag another word for?
Air resistance
Every force applies has a reaction force that is: ? (Two things
Equal in magnitude (size
Opposite in direction
What are the two forces of the same size (original and reaction) acting on?
Each other (so different objects)
What is the equation to work out momentum?
Momentum = mass x velocity
What is the SI unit for measuring momentum?
Kgm/s
What is the SI unit for measuring mass?
Kg
What is the SI unit for measuring velocity?
M/s
What type of quantity is momentum?
Vector quantity
What is important in momentum?
The Direction
What is momentum and what does this mean?
Momentum is constant, this means momentum before collision = momentum after collision
What is the other word for constant?
Conserved
What should we always assume in momentum questions unless told otherwise?
That there is no friction to slow things down
If an object moving in one direction has a positive momentum and there is an object traveling in an opposite direction, what type of momentum does this object have?
A negative momentum
When the question gives a direction in momentum what must you give in your answer?
The direction
