Forces Physics Topic 1 Flashcards
What are contact and non-contact forces?
What are some examples of them?
Contact forces are forces that have to make contact with something for it to react and an example of this would be friction and air resistance.
Non contact forces are forces that don’t need to make contact to function like gravitational pull and magnetic forces.
What is a force?
A push or pull that acts on an object due to the interaction with another object
Measured in Newtons
What can a force make an object do?
Change speed, direction and shape
What are examples of contact and non contact forces?
Contact: Friction, Air resistance, Lift, Tension
Non: Magnetic force, electrostatic force, gravitational force
What is a scalar?
Quantities which only have magnitude
(speed,mass,temperature)
What is a vector?
Quantities with both magnitude and direction (velocity,forces,displacement)
What is the equation for weight?
weight = mass x gravitational field strength
What are the units for weight, mass and gravitational field strength?
W=N
M=kg
G=N/kg
What is mass?
Amount of matter in an object
Fixed
What is weight?
The forces acting on an object due to gravity Not fixed
What is gravity?
The amount of force that acts on every kilogram
Not fixed
What is a resultant force?
When a number of forces acting on an object may be replaced by a single force that has the same effect as all the forces acting together
What are the steps to draw a resolving force?
1) Draw forces to scale
2) Box in as a parallelogram
3) Join dot to corner
4) Measure length and convert to scale
5) Measure the angle (bearing) clockwise from the vertical
What is work done?
When a force causes an object to move through a distance work is done on the object
What is the equation to find work done?
Work done(J) = force(N) x distance(m)
What is elastic and inelastic deformation?
Elastic-When an object has been stretched and returns to its original length after force has been removed
Inelastic-If the object doesn’t return to original shape and size
What is the equation to find a force from a spring?
Force(N) = spring constant(N/m) x extension (m)
What is Elastic Potential Energy?
The work done stretching or compressing a spring
What is the equation for Elastic Potential Energy?
EPE(J) = 1/2 spring constant(N/m) x extension^2(m)
What does Hookes Law state?
That a spring will always stretch by a proportional amount when force is increased
What is an elastic limit?
Furthest point a material can be stretched or deformed while be able to return to its previous state
What are the steps for a Hooke’s Law practical?
1) Attach a clamp to retort stand
2) Attach the spring to the clamp
3) Measure the spring without forces
4) Attach one 100g/1N weight to spring
5) Measure the new length of the spring
6) Subtract new length to original length to find extension
7) Repeat by adding more weights
8) Can plot it in a graph
What is the independent, dependent and control variable?
Independent-The variable being changed (eg. amount of weights)
Dependent-Variable being tested/measured (eg. the extension)
Control-Variable which is staying the same (eg. same spring, same amount of weight each time)
