P5 - Forces Flashcards
What is a vector quantity
Have a magnitude and a direction
Examples of vector quantities
Force, velocity, displacement , acceleration
What are scalar quantities
Have magnitude but no direction
Examples of scalar quantities
Speed, distance, mass, temperature, time
What is a contact force
When two objects have to be touching for a force to act, the force is a constant force
What is a non contact force
If the objects do not need tobe touching
What is mass
The amount of matter in an object
What is weight
Weight is the force acting on an object due to gravity
Waht does the weight of an object depend on
Its mass and the strength of the gravitational field it is in
How can you calcualate the weight of an object
Mass x gravitational Field strength
Relationship between mass and weight
They are directly proportional
What is resultant force
Number of forces acting on an object , can be replaced by a single force
What does a resultant force have the same effect as ?
All the original forces added together
When a force moves an object through a distance , energy is transferred
And work is done on the object
What has to happen to make an object move
A force must act on it
A force acts on an object .Causes energy
To be transferred to the object
Whwn you apply force to an object what may happen to it
May deform ,( stretch, compress or bend )
How many forces do you need to make an object deform
An object is deformed when more than one force is acting on the object.One force would just make the object move, not change the shape
What is elastically deformed
It can go back to original shape and length after force has been removed
What is inelastically deformed
If an object doesn’t go back how it was
When a force stretches or compresses then
Work has been done
When a force stretches a speing, causes it to
Extend
This extension in spring is what
Difference in length between the stretched and unstretched spring
What ia displacement
Measures the distance and direction in a straight line from an object’s starting point to its finishing point
What is speed
How fast gou are going
What is velocity
Velocity is speed in a given direction
Speed of person walking
1.5
Speed of person running
3
Speed of person cycling
6
Speed of a car
25
Speed of train
30
Speed of passenger plane
250
What is acceleration
Change in velocity in a certain amount of time
What is Newton’s First Law
If the reultsnt force on a stationary object is zero, the object will remain stationary.If the resultsnt force of a moving object is zero, carry on moving at same velocity
The larger the resultant force acting on an object is the
More the object accelerates
What is Newton’s second law
Says that the firce acting on an object and the acceleration of the object is directly proportional
What is Newton’s third law
When two objects interact, the forces they exert on each other are equal and opposite
What does Newton’s third law mean
Means if you push something , it will push you back against you, just as hard
Stopping distance =
Thinking distance + braking distance
What is thinking distance
How far the vehicle travels during the dirver’s resction time
What is braking distance
Distance taken to stop under the braking force
Stopping distance for different speeds can be estimated
The heavier a vehicle is, or the faster it is tracelling, the longer the stopping distsnce will be
What is your thinking distsnce be affected by
Your speed
Resction time
What is your braking distance affected by
A fast a vehicle travels , longer it tskes to stop.
Weather or road surface.If there is less grip on the road braking distance will be slower
Condition of your tyres
How good brakes are
