Practical 3 - Invstigation of Newton’s second law Flashcards
What does the gravitational force of the slotted masses do?
Causes the entire mass of the system to accelerate
What causes he entire mass of the system to accelerate?
The gravitational force of the slotted masses attached via a pulley
What makes up the entire mass of the system used?
Mass of rider (M)
Total mass of slotted masses (m)
m meaning
Total mass of slotted masses
M meaning
Mass or rider
What’s the alternative way of writing Newton’s second law that we can use to investigate it?
mg = (M+m)a
Which equation can be used to test Newton’s second law?
a = mg
——
(M + m)
How can we use a = mg/(M+m) to test Newton’s second law?
If the total mass of system (M and m) remains constant, then the acceleration, a, should be proportional to the gravitational force, mg.
What should be proportional in this practical and under which conditions?
Acceleration should be proportional to the gravitational force
(If the total mass of the system remains constant)
What’s the first step to completing this practical?
Fix the thread to the rider and attach five slotted 5g masses to the other end
What do we do after fixing the thread to the rider and attaching slotted masses to the other end?
Set the light gates to record the acceleration and allow the slotted masses to fall to the ground
How do we calculate mg?
Mass (in kilograms) x g
How do we calculate the acceleration in this practical?
It’s recorded by the light gates
What do we do after recording the acceleration for a particular run with the masses?
Remove one of the slotted masses and place it on the rider (so keeping the total mass constant)
What do we do with the masses after each run?
Remove one of the slotted masses and place it on the rider (the total mass of the system remains constant)
What remains constant throughout this practical?
The total mass of the system
Until when do we repeat this experiment?
Until all of the different accelerating masses have been removed
How do we plot the graph for this practical and what should it show?
Acceleration on the y-axis
Gravitational force (mg) on the x-axis
It should be a straight line through the origin to show that they’re directly proportional
Which part of the new way of writing Newton’s second law is used to represent the gradient?
1
—
(Mxm)
How do we work out the total mass (M+m) in our system?
1
—. = gradient
(M+m)
(M+m) = 1
——
Gradient
How do we work out our gradient?
Change in y
——————
Change in x
(From our graph)
How do we work out our % difference between the actual mass and the mass calculated for the system?
Difference
————— x100
Actual
What does the 1/(M+m) equation give us?
Our gradient
What % difference between our actual value and our calculated value gives us a reliable result?
5% or less
What does a 5% or less difference between our calculated mass and the actual mass mean?
That we have reliable results and that the experiment was a success
Which equation is used to get the equation for the gradient and what is this?
a = mg
——
(M+m)
Gradient = 1
——
(M + m)
How do we eliminate the effects of gravity?
Ensure that the track is level
