Question #2983d

1 Answer
Mar 26, 2017

Answer:

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