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Instantaneous velocity problem

  • #1

Homework Statement


find the instantaneous velocity of the particle described in figure 1.1 at the following time a.) t=3.0 s.



Homework Equations


instantaneous velocity equals dx/dt
in the graph, 3 seconds of time is equal to 8 meters.



The Attempt at a Solution



so would the answer just be the derivitive of 8/3? i dont get how to use the formula. because then the answer would just be zero, right?
 

Answers and Replies

  • #2
580
0

Homework Statement


find the instantaneous velocity of the particle described in figure 1.1 at the following time a.) t=3.0 s.



Homework Equations


instantaneous velocity equals dx/dt
in the graph, 3 seconds of time is equal to 8 meters.



The Attempt at a Solution



so would the answer just be the derivitive of 8/3? i dont get how to use the formula. because then the answer would just be zero, right?
dx/dt gives you the slope of the tangent drawn to point at which you need the instantaneous speed. I presume that you have a displacement versus time graph. Draw a tangent to the point at t=3 and fine the slope of the tangent.
Otherwise more accurately, if you could express displacement as a function of time from the structure of the graph an then differentiate it, it would be better.
regards,
Ritwik
 
  • #3
73
0
if the acceleration is zero (a=0) then x=v*t+x0 so the answer is 8=v*3+x0 and if x0=0 then the answer is v=8/3
and also v=dx/dt then dx=v*dt and if you integrate this equation you will get x-x0=v*t
 

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