Acar traveling at 28 m/s starts to decelerate steadily. it comes to a complete stop in 13 seconds. what is its acceleration?

Acceleration = (change in speed) / (time for the change)

change in speed = (speed at the end) minus (speed at the beginning)

change in speed = (zero) minus (28 m/s) = -28 m/s

Acceleration = (-28 m/s) / (13 sec)

Acceleration = -2.15 m/s²

1 hour

Explanation:

Speed of the first boat = 30 mph

Speed of the second = 40 mph

The boats will cover different distances but the time taken will be the same.

Time taken by the boats = t

Distance = Speed × Time

Distance covered by the first boat = 30t

Distance covered by the second boat = 40t

Distance between the boats = 50 mi

From the Pythagoras theorem

Time taken by the boats when they are 50 mi away is 1 hour