# Question #2983d

##### 1 Answer

Mar 26, 2017

The ball weighs

#### Explanation:

Kinetic energy is found by the formula:

#KE = 1/2mv^2#

We know that

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Now, let's plug in everything we know and solve for

#1000 color(white)".""J" = 1/2 M * (5 color(white)"." "m/s")^2#

#1000 color(white)"." J = 1/2 M * 25 color(white)"." "m"^2"/s"^2#

#40 color(white)"." "kg" = 1/2 M#

#80 color(white)"." "kg" = M#

*Final Answer*