Question

An object is dropped from the top of a building. How fast is it moving after 15 s? What is the acceleration at this time?

Answer 1

Answer: 147m/s

Step-by-step explanation:

You can use the first kinematic equation stating that:

`V_f=V_i+at`

The object was dropped from the top of the building, therefore the initial velocity at t = 0 is zero. The acceleration of the object in free fall will always be due to the gravitational field, under the assumption air resistance is negligble. So, the equation reduces to:

`V_f=(9.8m/s^2)(15s)=147m/s`