Kinematics: given 2 position vectors, time, and V of earlier

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SUMMARY

The discussion focuses on calculating various kinematic quantities given two position vectors, a time interval, and the initial velocity of a particle. Participants concluded that while average velocity and displacement can be calculated using the provided data, the calculation of final velocity and average acceleration requires specific conditions. The relationship for final velocity, expressed as Vaverage = (1/2)(Vinitial + Vfinal), is valid only under constant acceleration, which is a critical condition for its application.

PREREQUISITES
  • Understanding of kinematic equations
  • Familiarity with position vectors
  • Knowledge of average velocity and displacement calculations
  • Concept of constant acceleration in physics
NEXT STEPS
  • Study the derivation of kinematic equations under constant acceleration
  • Explore the implications of average velocity in non-uniform motion
  • Learn about the conditions for applying the average velocity formula
  • Investigate the relationship between displacement and time in various motion scenarios
USEFUL FOR

Students of physics, educators teaching kinematics, and anyone interested in understanding the principles of motion and velocity calculations.

Dillon Keeler
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If you know the position vectors of a particle at two points along its path, change in time between the two positions, and the particle's velocity at the earlier point, what quantities can you calculate?

a)average acceleration
b)final velocity
c)average velocity
d)displacement

My answer was all of the above because one can find
d) by just the two position vectors
c) by ( displacement / change in time )
b) by Vaverage= (1/2)(Vinitail+Vfinal)
a) by average acceleration = ( change in velocity / change in time)

however the answer is just c) and d). Am I forgetting to take something in consideration?
 
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Your "b" is true only for a special case. It is not a generally valid relationship.
Do you know what is this special case? What is the condition to have this relationship?
 
nasu said:
Your "b" is true only for a special case. It is not a generally valid relationship.
Do you know what is this special case? What is the condition to have this relationship?
Constant Acceleration?
 

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