Question

the kinetic energy of an object is moving with the mass m with the velocity of 10 m/s is 100j find the k.e when velocity is doubled​

Answer 1

Answer:-

Kinetic energy of the body when velocity is doubled is 400J

Explanation:-

We have :-

❋ Mass of the body is "m"

❋Velocity is 10 m/s

❋Kinetic energy is 100J

Required to find :-

Kinetic energy when the velocity is doubled .

Sᴏʟᴜᴛɪᴏɴ :-

Firstly lets find the mass of the body.

We know that,

$\: \: \: \: \: \boxed{ \bf \: K.E \: = \frac{1}{2} mv {}^{2} }$

where,

K.E = Kinetic energy

m = mass

v = velocity

Let's find the mass of the body when velocity is 10 m/s and K.E is 100J and mass is *m*

$\: \: \: \: \: \implies \: \tt \: 100 = \dfrac{1}{2} \times m \times (10) {}^{2}$

$\: \: \: \: \: \implies \: \tt \: 100 = \dfrac{1}{2} \times m \times 100$

$\: \: \: \: \: \implies \: \tt \: \cancel{100} = \dfrac{1}{2} \times m \times \cancel{100}$

$\: \: \: \: \: \implies \: \tt1 = \dfrac{m}{2}$

$\boxed{ \bf \: m \: = 2kg}$

So, mass of the body is 2kg.

Now we need to find the K.E when velocity is doubled and mass is 2kg

Velocity doubled i.e 10 m/s = 2(10 ) = 20 m/s

Putting down the values,

$\: \: \: \implies \tt \: K.E \: = \dfrac{1}{2} \: \times 2 \times (20) {}^{2}$

$\: \: \: \implies \tt \: K.E \: = \dfrac{1}{ \not2} \: \times \not2 \times 400$

So,

$\boxed{ \bf \: K.E \: = 400J}❋$

Answer 2

kinetic energy will be 200J

 

as we know kinectic energy is equals to

             KE = 1/2 ×M× V∧2

M = MASS

V= VELOCITY

therefore, initial kinetic energy = 100j =1/2×M ×10×10 by above question

final kinetic energy = 1/2 ×M ×20×20 =200J  ( as initial velocity was given 10 m/s so its double would be 20m/s)

Hence answer of this question is 200J.