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**1. (a)A train slows down at a constant rate as it**

rounds a sharp circular horizontal turn. Its

initial speed is not known. It takes 16.6 s to

slow down from 86 km/h to 30 km/h. The

radius of the curve is 162 m.

As the train goes around the turn, what is

the magnitude of the tangential component of

the acceleration?

Answer in units of m/s2.

(b) As the train goes around the turn, what is

the sign of the tangential component of the

acceleration? Take the direction in which the

train is moving to be the positive direction.

1. +

2. Not enough information

3. 0

4. −

(c)At the moment the train’s speed is 50 km/h,

what is the magnitude of the total accelera-

tion?

Answer in units of m/s2.

rounds a sharp circular horizontal turn. Its

initial speed is not known. It takes 16.6 s to

slow down from 86 km/h to 30 km/h. The

radius of the curve is 162 m.

As the train goes around the turn, what is

the magnitude of the tangential component of

the acceleration?

Answer in units of m/s2.

(b) As the train goes around the turn, what is

the sign of the tangential component of the

acceleration? Take the direction in which the

train is moving to be the positive direction.

1. +

2. Not enough information

3. 0

4. −

(c)At the moment the train’s speed is 50 km/h,

what is the magnitude of the total accelera-

tion?

Answer in units of m/s2.

## Homework Equations

atangential = d|v|/dt

not sure on others

## The Attempt at a Solution

I tried part (a) with atangential = d|v|/dt

where atangential = |30-86|/16.6=3.37349 km/h^2

then converting to m/s^s by times 3600s and dividing 1000m and getting 12.1446 m/s^2

wrong