Question

What is the best description of the acceleration of an object?

Question 5 options:

A runner travels 100 m in one minute.


A car's velocity changes from 25 m/s to 20 m/s in 5 seconds.


An airplane changes elevation from 10,000 ft to 5,000 ft.


A remote-control car speeds up.

Answer 1

The second one
Because acceleration is a change in velocity/speed
so the car would be going -1m/s/s
:)

Answer 2

Answer : The correct option is a car's velocity changes from 25 m/s to 20 m/s in 5 seconds.

Explanation :

Acceleration : It is defined as the change in velocity divided by the time.

The formula of Acceleration is,

`Acceleration=\frac{\text{ (final velocity)-(initial velocity)}}{Time}=\frac{\text{ Change in velocity}}{Time}`

So, we can calculate the acceleration only for 2nd option which is a car's velocity changes from 25 m/s to 20 m/s in 5 seconds.

In this option, velocities and time are given.

`Acceleration=((25m/s)-(20m/s))/(5s)=1m/s^2`

In all the other options, the velocity and time are not given. So, we can not calculate the acceleration.

Hence, the correct option is a car's velocity changes from 25 m/s to 20 m/s in 5 seconds.