Classical mechanics - hunter and monkey - frame of reference

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SUMMARY

The discussion centers on the classical mechanics scenario involving a hunter and a monkey, as explained by Professor Walter Lewin. The key conclusion is that in Newtonian mechanics, time is invariant across different frames of reference, whether they are accelerating or static. Despite the monkey's acceleration, the time it takes for the bullet to hit the monkey remains the same in both frames. This is due to the principle that what happens cannot depend on the frame of reference, affirming that the presence of gravity only alters the path of the objects, not the time of impact.

PREREQUISITES
  • Understanding of Newtonian mechanics
  • Familiarity with frames of reference
  • Basic knowledge of kinematics
  • Concept of acceleration in physics
NEXT STEPS
  • Study the implications of non-inertial frames in classical mechanics
  • Explore the concept of time invariance in Newtonian physics
  • Learn about the differences between Newtonian mechanics and relativistic physics
  • Investigate the effects of gravity on projectile motion
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This discussion is beneficial for physics students, educators, and anyone interested in understanding the principles of classical mechanics and the behavior of objects in different frames of reference.

ethanhunt
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Hi,

This might sound very basic and but i am just starting to learn physics.
I an lecture by prof. walter lewin, he descibes the hunter and monkey scenario. The monkey jumps from the tree as soon as the hunter aims and shoot his gun. the bullet hits the monkey anyway.
In calculating the time it takes the bullet to hit the monkey, he calculates from monkey's frame of reference and class's frame of reference to be same. He also states that the time is same irrespective of a moving frame (monkey's) and static frame (Class).

My doubt is, the monkey is accelerating with respect to the class. So the time and speed of bullet should not be the same for both as one is accelerating. From what i understand, an accelerating frame of reference will not produce same results as relative velocities will differ.
Please let me know your thoughts on this. Am i missing something?

Thanks
EthanHunt
 
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What happens cannot depend on the frame of reference, whether accelerating or not. The monkey is either hit or not.

In Newtonian mechanics, time is invariant between different frames and so the time must also be the same in all reference frames. (This is different in relativity, but monkeys are not that fast.)
 
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Hi Orodruin,

Thank you for the explanation. I tried measuring the time taken when the 2 are only along the vertical and it does work out. So as i understand the presence of gravity only alters the path of the objects. As such the time taken is the same else the monkey does not get hit.

I think i understand. the non inertial frame concept affects the Newton's laws as seen in the non inertial frame of reference. The behavior will not conform to the laws.
So in Newtonian mechanics, both frames measure the time at the same rate but the cause / effect will not make sense. We cannot predict the behavior correctly.
 

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