Forces and Inclined plane (ramp)

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SUMMARY

The discussion focuses on deriving the acceleration of a ramp (mass M) with a block (mass m) on it, inclined at angle θ, in a frictionless environment. The initial approach involved calculating the normal force and its horizontal component but proved incorrect. The correct solution utilizes the concept of pseudo force and a reference frame moving with the ramp, allowing for the application of Newton's laws to establish the relationship between the block's vertical and horizontal motions. The final expression for the ramp's acceleration is derived successfully using these principles.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Familiarity with the concept of pseudo force
  • Knowledge of basic trigonometry (sine and cosine functions)
  • Ability to apply kinematics equations in physics problems
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  • Research the concept of pseudo force in non-inertial reference frames
  • Study the application of Newton's laws in systems with multiple moving bodies
  • Explore advanced problems involving inclined planes and frictionless surfaces
  • Learn about the relationship between vertical and horizontal motion in physics
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Students studying physics, particularly those focusing on mechanics, as well as educators looking for examples of inclined plane problems and the application of Newton's laws in dynamic systems.

homo-sapiens
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Homework Statement



A block of mass m is held in place on a ramp of mass M with a slope of angle θ, which in turn is held in place as shown in the figure below. The ramp is free to move on the surface beneath it. There is no friction anywhere. The block and the ramp are then released. Derive an expression for the magnitude of the acceleration of the ramp. (Use any variable or symbol stated above along with the following as necessary: g. Assume SI units.)

Homework Equations



f=ma[/B]

The Attempt at a Solution


[/B]
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since the ramp is pushing on the mass, the mass is also pushing back on the ramp with a force N (normal force). and to find the horizontal component of the normal force, I did sin0 times Force N. and force N = cos0mg. therefore i concluded the acceleration should be sin0*cos0*mg / M. But it's not correct, can someone explain this and tell me why?
 
The normal force will be different as the ramp is receding from the block (compared to the standard block-on-a-ramp problem).
You'll have to set up forces for both objects at the same time, and find a relation between the vertical and horizontal motion of the small block (it is not following the angle of the slope).
 
should I introduce kinematics equations into this problem?? or would I be able solve this problem with only Newton's three laws??
 
homo-sapiens said:
should I introduce kinematics equations into this problem?? or would I be able solve this problem with only Newton's three laws??
I think that this can be easily solved with Newton's three laws.Do you know the concept of pseudo force?
It will be easier to solve the problem by choosing a reference frame that is moving with the wedge.
 
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pseudo force? thanks. you will look into ot
 
i will look into it . sorry tablet typo
 
homo-sapiens said:
i will look into it . sorry tablet typo
Ok. Please reply if you need help.
 
ok, solved it by using pseudo force. Thank you so much for the tip. Still a bit confused on what pseudo force is but I will manage. Thank you again.
 
  • #10
homo-sapiens said:
ok, solved it by using pseudo force. Thank you so much for the tip. Still a bit confused on what pseudo force is but I will manage. Thank you again.
You are welcome.:)
 

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