Classical mechanics -- Equations for simulating the motion of a body

In summary, you would need a differential equation for the motion, and a prescription for the forces applied to the body.
  • #1
s1mos_tsr
4
0
Hello forum, i want to make a samulation of a body. The body will be moved horisontal on y,x axis. I want on my simulation the body to change direction many times(for example i want to go for 10sec right and then left end right...). My question is does i need more than one differential equation to describe this type of motion?
thanks in advance lovers of physics
 
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  • #2
Hello @s1mos_tsr , :welcome: !

What causes the body to move/change direction ?
As a minimum you don't need a differential equation at all, just a prescription for the motion...
 
  • #3
Lets say that the object has a inside mechanins to produce force, for example at t=0 a instand force make the object to move right and at t=10 a counterforce make the object to move left. In my mind i have a plan to make a dynamic model to have the simulation i don't know if this is the right method.
 
  • #4
s1mos_tsr said:
Lets say that the object has a inside mechanins to produce force, for example at t=0 a instand force make the object to move right and at t=10 a counterforce make the object to move left. In my mind i have a plan to make a dynamic model to have the simulation i don't know if this is the right method.
Welcome to the PF. :smile:

Can you say a bit about your background so far in math and physics? Are you familiar with Newton's Laws of Motion?

https://en.wikipedia.org/wiki/Newton's_laws_of_motion

Are you familiar with drawing a Free Body Diagram (FBD) of an object to help in calculating the motion resulting from forces and torques ("moments") applied to the body?
 
  • #5
I am studying mechanical engineering and i started a project about control systems. My project is to make a simulation on MATLAB of an inverted pendulum but because its a little bit deep for me i wanted to start a easier simulation on MATLAB like a free fall body and moving body on surface. My goal is to achieve the control the pendulum. I want also to make it more visual and try to animate the simulation. I have good background on statics systems but on the dynamics models i am not so good. My main question this moment what i said at the 1st post and also how to describe with maths the change of force that makes the body to change direction.
** at t=0 a instand force make the object to move right and at t=10 a counterforce make the object to move left
 
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  • #6
Well, if you use stepwise continuous vector forces, you can use the kinematic equations of motion for constant acceleration, which simplifies things a lot, right? Maybe start with that, and then later move on to discrete simulations of motion where the forces vary with time.

What would the motion of a 1kg mass be like given this piecewise continuous force profile?

##0s < t \leq 1s : F = 1N \hat x##
##1s < t \leq 2s : F = 3N \hat y##
## 2s < t \leq 3s : F = -2N \hat x##
 
  • #7
Ok i think i get it a little bit. The point is to change the force(by changing the the sign) while the code is running at the time you want, correct me if i am wrong. But on the image i don't understand what N and X(hat) represents there.
 
  • #8
##N## is Newton, SI unit of force (kg m/s2)
##\hat x## is a unit vector in the ##x##-direction
 

FAQ: Classical mechanics -- Equations for simulating the motion of a body

What is classical mechanics?

Classical mechanics is a branch of physics that deals with the motion of macroscopic objects, such as particles, bodies, and systems of bodies, under the influence of forces.

What are the basic equations used in classical mechanics?

The basic equations used in classical mechanics are Newton's laws of motion, which state that an object will remain at rest or in uniform motion unless acted upon by an external force, and that the force acting on an object is equal to its mass multiplied by its acceleration.

How are these equations used to simulate the motion of a body?

To simulate the motion of a body, the equations of motion are solved numerically using computational methods. This involves breaking down the motion into small time intervals and calculating the position and velocity of the body at each interval based on the forces acting on it.

What factors can affect the accuracy of simulations using classical mechanics equations?

The accuracy of simulations using classical mechanics equations can be affected by factors such as the precision of the initial conditions, the choice of numerical method, and the inclusion of external factors such as air resistance or friction.

Are there any limitations to using classical mechanics equations for simulating motion?

While classical mechanics equations are highly accurate for describing the motion of macroscopic objects, they do have limitations. These equations do not apply to objects moving at speeds close to the speed of light, or to objects at the atomic or subatomic level, for which quantum mechanics equations are needed.

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