Question

a train is moving in the positive direction down a track. First the train speeds up, and then it slow what is its acceleration?

Answer 1

If the train first speeds up and then slows down, its acceleration will:

1. Be positive when it speeds up
2. Be negative when it slows down

More specifically:

When the train first speeds up, its velocity (speed and direction) is increasing. According to the definition of acceleration, when velocity is increasing, acceleration is positive.

So during the speeding up portion, the train's acceleration will be positive.

Then, when the train begins to slow down, its velocity is decreasing. Based on the definition of acceleration, when velocity is decreasing, acceleration is negative.

So during the slowing down portion, the train's acceleration will be negative.

Since the question asks for the acceleration in general terms, without specifying a particular time, the overall acceleration would be:

First positive, when the train speeds up

Then negative, when the train slows down

In summary:

• When an object speeds up, its acceleration is positive
• When an object slows down, its acceleration is negative
• Since the train first speeds up and then slows down, its acceleration will first be positive, then negative
• The overall acceleration is not specified as a single value, but rather changes from positive to negative as the train's speed changes

Answer 2

it has a positive acceleration first then a mega acceleration