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Kinematics Basics

  • Thread starter adoado
  • Start date
  • #1
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Homework Statement



The acceleration of a particle is defined by a = -8 m/sec2. Knowing that x = 20 when t = 4 and x = 4 when v = 16, determine:

  • The time when the velocity is zero
  • The velocity and the total distance travelled when t = 11

Homework Equations





The Attempt at a Solution



I think once I get part 'a' I can do part 'b'. Here is my attempt:

a = -8m/sec2
So
V = -8t + C.

How can I get C? Do I need to use another representation of acceleration? I am not sure where to go.

Any advice greatly appreciated!
Adrian
 

Answers and Replies

  • #2
CompuChip
Science Advisor
Homework Helper
4,302
47
C is the velocity at time t = 0.
I would suggest using the formula
s(t) = (1/2) a t² + C t + D (*)
where C is the velocity v(0) at time t = 0 and D is the displacement s(0) at t = 0.

If you plug in the two given points you can determine C and D. Then you can use both formula (note that v(t) = -8t + C will actually be the derivative of formula (*) above).
 

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