Find displacement from a record of travel

[tacobeans1234]

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

 

[lewando]

Part (c) looks off. What did you do to get that answer? BTW, negative acceleration of -10.4m/s² is a double negative.

 

[PeterO]

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.