Effie
2003-09-10 08:24:14 UTC
Hello everyone, and thanks and in advance for any help that may be provided.
I am a year 12 student, undertaking physics, and am currently completing a
big research project to end the year.
My topic is motion, and i am attempting to study or investigate the physics
of a catapult.
Prior to choosing the topic of my investigation, i knew nothing of the
theory surrounding catupult mechanics.
I have a basic year 12(Australian education system) understanding of
kinematics, and this does not encompass anything to do with catapults.
For simplicity, i have decided to keep my catapult basic.
It is simply a see-saw, where one side will be the counter weight, and the
other the projection arm. The fulcrum is centralised.
And, to project an object, the counterweight will be raised, then let go. A
bar will stop the turning arm at a certain angle, allowing inertia to
project the projectile.
To contrast my measurements, i would obviously like some theoretical
predictions. Problem is, i have no formulae to use, and i have attempted to
formulate some mathematical
modelling, which i am not sure about. I thought of trying to consider the
force exerted on the arm by the counterweight as the same as a basic
inclined plane problem, where the force acting down the plane =
m.g.Sin(theta), except, theta is constantly changing. This gave me vector
equations for the acceleration in terms of the angle at which the arm is at,
which can obviously give me velocity and displacement through integration.
Acceleration(vector) = (-9.8 * Sin(theta) * Cos(Theta))i + (-9.8 *
Sin(theta) * Sine(theta))j
I figured torques would also come into it as well, which in addition to my
previous doubts, made me rather unconfident in my mathematical attempts.
My aim is to, find the resultant or the sum of all the forces or torques
that will act on the see-saw or arm, correlate this to an acceleration and
in turn dertimine the velocity at which the arm is travelling at any point,
and therefore, predict the projectilies motion on the basis of this
theoretical initial velocity.
I will persist with my maths and theory, but i was wondering if anyone knew
the theory behind such a basic system, and could guide me as to how i can
predict the projectiles intitial velocity. Surprisingly, my teachers are
rather ignorant on the topic!? Thanks in advance for any assistance.
I am a year 12 student, undertaking physics, and am currently completing a
big research project to end the year.
My topic is motion, and i am attempting to study or investigate the physics
of a catapult.
Prior to choosing the topic of my investigation, i knew nothing of the
theory surrounding catupult mechanics.
I have a basic year 12(Australian education system) understanding of
kinematics, and this does not encompass anything to do with catapults.
For simplicity, i have decided to keep my catapult basic.
It is simply a see-saw, where one side will be the counter weight, and the
other the projection arm. The fulcrum is centralised.
And, to project an object, the counterweight will be raised, then let go. A
bar will stop the turning arm at a certain angle, allowing inertia to
project the projectile.
To contrast my measurements, i would obviously like some theoretical
predictions. Problem is, i have no formulae to use, and i have attempted to
formulate some mathematical
modelling, which i am not sure about. I thought of trying to consider the
force exerted on the arm by the counterweight as the same as a basic
inclined plane problem, where the force acting down the plane =
m.g.Sin(theta), except, theta is constantly changing. This gave me vector
equations for the acceleration in terms of the angle at which the arm is at,
which can obviously give me velocity and displacement through integration.
Acceleration(vector) = (-9.8 * Sin(theta) * Cos(Theta))i + (-9.8 *
Sin(theta) * Sine(theta))j
I figured torques would also come into it as well, which in addition to my
previous doubts, made me rather unconfident in my mathematical attempts.
My aim is to, find the resultant or the sum of all the forces or torques
that will act on the see-saw or arm, correlate this to an acceleration and
in turn dertimine the velocity at which the arm is travelling at any point,
and therefore, predict the projectilies motion on the basis of this
theoretical initial velocity.
I will persist with my maths and theory, but i was wondering if anyone knew
the theory behind such a basic system, and could guide me as to how i can
predict the projectiles intitial velocity. Surprisingly, my teachers are
rather ignorant on the topic!? Thanks in advance for any assistance.