Question

Mass 300g velocity..vector 3i+4j what is kinetic energy

Answer 1

mass = 300 g = 0.3 kg

magnitude of the velocity vector = √3²+4²

                                                       = √25

                                                       = 5 m/s

kinetic energy = 1/2×m×v²

                       = 1/2 × 0.3 × 25

                       = 7.5/2

                       = 3.75 joules

Answer 2

Answer:

If velocity is V=3i+4j and the mass of the body is 300g, its kinetic energy is  

Explanation:

• The kinetic energy of a particle with mass (m) with velocity (v) is equal to

        $KE=\frac{1}{2}mv^{2}$

• If vector A is $A=ai+bj+ck$ its magnitude is $/A/=\sqrt{a^{2} +b^{2} +c^{2} }$

From the question, we have

mass of the body $m=300g=0.3kg$

velocity in vector form $v=3i+4jm/s$

magnitude of velocity $/v/=\sqrt{3^{2} +4^{2} }$

⇒$/v/=\sqrt{25}=5m/s$

now the kinetic energy of the body

$KE=\frac{1}{2} *0.3*5 ^{2}$

⇒$KE=3.75J$