TS EAMCET · Physics · Work Power Energy
The kinetic energy of a body of mass 4 kg moving with a velocity of \((2 \hat{i}-4 \hat{j}-\hat{k}) \mathrm{ms}^{-1}\) is
- A 84 J
- B 63 J
- C 42 J
- D 21 J
Answer & Solution
Correct Answer
(C) 42 J
Step-by-step Solution
Detailed explanation
\begin{aligned} & \mathrm{m}=4 \mathrm{~kg}, \overrightarrow{\mathrm{v}}=(2 \hat{\mathrm{i}}-4 \hat{\mathrm{j}}-\hat{\mathrm{k}}) \mathrm{ms}^{-1} \\ \therefore & \mathrm{v}=|2 \hat{\mathrm{i}}-4 \hat{\mathrm{j}}-\hat{\mathbb{k}}|=\sqrt{(2)^2+(-4)^2+(-1)^2}=\sqrt{21} \\…
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