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Find displacement from a record of travel

  • #1

Homework Statement



A record of travel along a straight path is as
follows:
(a) Start from rest with constant acceleration of 3.95 m/s
2
for 16.5 s;
(b) Constant velocity of 65.175 m/s for the
next 0.789 min;
(c) Constant negative acceleration of
−10.4 m/s
2
for 3.52 s.
What was the total displacement x for the
complete trip?
Answer in units of m

Homework Equations



I had my physics teacher help me along. I know that you need to find and add all of the displacements, but I still can't seem to get the right answer.

The Attempt at a Solution


I don't remember exactly what I did, but I got these numbers for the displacement for each section of the problem.
a)537.694
b)3085.38
c)-36.608
 

Answers and Replies

  • #2
lewando
Homework Helper
Gold Member
1,340
134
Part (c) looks off. What did you do to get that answer? BTW, negative acceleration of -10.4m/s2 is a double negative.
 
  • #3
PeterO
Homework Helper
2,425
46

Homework Statement



A record of travel along a straight path is as
follows:
(a) Start from rest with constant acceleration of 3.95 m/s
2
for 16.5 s;
(b) Constant velocity of 65.175 m/s for the
next 0.789 min;
(c) Constant negative acceleration of
−10.4 m/s
2
for 3.52 s.
What was the total displacement x for the
complete trip?
Answer in units of m

Homework Equations



I had my physics teacher help me along. I know that you need to find and add all of the displacements, but I still can't seem to get the right answer.

The Attempt at a Solution


I don't remember exactly what I did, but I got these numbers for the displacement for each section of the problem.
a)537.694
b)3085.38
c)-36.608

Yes part (c) wrong. This body doesn't even stop by that time.

With an initial velocity of 65, and an acceleration of -10, it will have merely slowed to 30 m/s. Use the real numbers to get the real answer.
 

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