(C) Given: Mass $m = 4 \ kg$. Velocity vector $\vec{v} = (2 \hat{i} - 4 \hat{j} - \hat{k}) \ ms^{-1}$.First,calculate the magnitude of the velocity $v

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(C) Given: Mass $m = 4 \ kg$. Velocity vector $\vec{v} = (2 \hat{i} - 4 \hat{j} - \hat{k}) \ ms^{-1}$.First,calculate the magnitude of the velocity $v = |\vec{v}| = \sqrt{(2)^2 + (-4)^2 + (-1)^2}$.$v = \sqrt{4 + 16 + 1} = \sqrt{21} \ ms^{-1}$.The kinetic energy $K.E.$ is given by the formula $K.E. = \frac{1}{2} mv^2$.Substituting the values: $K.E. = \frac{1}{2} \times 4 \times (\sqrt{21})^2$.$K.E. = 2 \times 21 = 42 \ J$.

Class 11 Physics Work, Energy, Power and Collision Kinetic Energy

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The kinetic energy of a body of mass $4 \ kg$ moving with a velocity of $(2 \hat{i}-4 \hat{j}-\hat{k}) \ ms^{-1}$ is (in $J$)

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A
$84$
B
$63$
C
$42$
D
$21$

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Work, Energy, Power and Collision

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Kinetic Energy

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The kinetic energy of a body of mass $4 \ kg$ moving with a velocity of $(2 \hat{i}-4 \hat{j}-\hat{k}) \ ms^{-1}$ is (in $J$)

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