Question

An object of 120 kg is moving with a velocity of 4.5 m/s. Find the amount of Kinetic

Energy it possess.​

Answer 1

Given:-

• Mass of the object = 120kg

• Initial Velocity = 4.5m/s

To Find:-

• The Amount of Kinetic energy it Possess.

Formulae used:-

• Kinetic Energy = ½ × mv²

Before Solving let us know what is Kinetic enrgy.

When a body is moving with some Velocity it is said to Posses kinetic Energy.

Suppose a body with mass m moving with Velocity v. Some work is done on the body that's why it is moving.

So,

W = F × s...........1

Newton's third Equation of motion says that

v² - u² = 2as.

s = (v² - u²)/2a........2

Also,

F = ma...........3

Now, Putting the value of 2 and 3 in eq. 1

Therefore,

→ w = F × s

→ w = ma × (v² - u²)/2a

→ w = m × (v² - u²)/2

But u = 0 as body will stars from rest

→ w = mv²/2

The amount of work done is equal to Kinetic energy if object

Hence,

K.E = mv²/2

Now,

→ Kinetic energy = ½ × mv²

→ K.E = ½ × 120 × (4.5)²

→ K.E = ½ × 120 × 20.25

→ K.E = 60 × 20.25

→ K.E = 1215J

Hence, The Kinetic Energy Posses by object is 1215J.

Answer 2

Explanation:

$\large{ \sf \underline{ \red{Given : - }}}$

• An object of 120 kg is moving .

• a velocity of 4.5 m/s.

$\large{ \sf \underline{ \red{To\:Find : - }}}$

• Find the amount of Kinetic

$\large{ \sf \underline{ \red{Solution : - }}}$

We have Formula

$\boxed{ \sf \orange{Kinetic \: Energy = \frac{1}{2} \times {mv}^{2} }}$

putting all values

$\sf \to \: K.E = \frac{1}{2} \times120 \times 4.5^2 \\ \\ </p><p></p><p> \sf \to K.E = \frac{1}{ \cancel{2}} \times \cancel{ 120 }\times 20.25</p><p> \\ \\ </p><p> \sf \to \: K.E = 60 \times20.25 \\ \\ </p><p></p><p> \sf \to \red{K.E = 1215.00J }\\ \\ \\ \\ </p><p>$

Hence the amount of the amount of Kinetic is 1215

$\large{ \sf \underline{ \red{More\: information : - }}}$

• kinetic energy of an object is the energy that it possesses due to its motion.

• It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.

• Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes.