Question

If v = 3i+4j+5k is the instantaneous velocity of a body of mass 1.50 kg. Calculate its kinetic energy

Answer 1

The kinetic energy of the body is 37.48 Joules.

Explanation:

Velocity of a body, v=3i+4j+5k

magnitude of velocity, $v=\sqrt{3^2+4^2+5^2} =7.07\ m/s$

Mass of the body, m = 1.5 kg

It is required to find the kinetic energy of the body. The formula of the kinetic energy is given by :

$K=\dfrac{1}{2}mv^2\\\\K=\dfrac{1}{2}\times 1.5\times (7.07)^2\\\\K=37.48\ J$

So, the kinetic energy of the body is 37.48 Joules.

Learn more,

Kinetic energy

https://brainly.in/question/14653288

Answer 2

Answer:

If velocity of a body is  $v=3i+4j+5k$ and mass of the body is $1.5kg$, its kinetic energy is $37.5J$

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 $m=1.5kg$

velocity in vector form $v=3i+4j+5k$

magnitude of velocity $v=\sqrt{3^{2} +4^{2} +5^{2} }$

⇒$v=\sqrt{50}=7.07m/s$

now the kinetic energy of the body

$KE=\frac{1}{2} (1.5)(7.07) ^{2}$

⇒$KE=37.5J$