# If an object is dropped, how fast will it be moving after falling #21 m#?

##### 2 Answers

Jun 29, 2018

#### Explanation:

Use equation of motion

#"v"^2 - "u"^2 = "2aS"#

Where

#"v ="# Final velocity#"u ="# Initial velocity#"a ="# Acceleration#"S ="# Displacement

The object is dropped. So

#### Explanation:

**Using the formula:**

where;

#v# is the**final velocity**of the object which we**need**to find.#u# is the**initial velocity**of the object, which is#0# since it fell from**rest**.#a# is the**acceleration of free fall**#("9.81 m s"^-2)# #s# is the**displacement**, which is#"21 m"#

Now all you gotta do is substitute:

So