Explanation:
mass=50g
velocity=42cm/s
Kinetic energy
As we know that
[tex]{\boxed{\sf kinetic\:energy={\dfrac {1}{2}}mv^2}}[/tex]
[tex]{:}\longrightarrow[/tex][tex]\sf k.v={\dfrac {1}{{\cancel{2}}}}\times 50\times {\cancel{42}}^2 [/tex]
[tex]{:}\longrightarrow[/tex][tex]\sf k.v=50\times 21^2 [/tex]
[tex]{:}\longrightarrow[/tex][tex]\sf k.v=50×441 [/tex]
[tex]{:}\longrightarrow[/tex][tex]\sf k.v=22050MJ [/tex]
[tex]\therefore[/tex][tex]{\underline{\boxed{\bf Kinetic\:energy=22Joule}}}[/tex]