Question

Question #2983d

Answer 1

The ball weighs `80 color(white)"." "kg"`

Explanation:

Kinetic energy is found by the formula:

`KE = 1/2mv^2`

We know that `KE = 1000 color(white)"." J`, and `v = 5 color(white)"." "m/s"`. Let's call the mass `M` to avoid confusion between the mass variable and the symbol for meters.
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Now, let's plug in everything we know and solve for `M`.

`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