Question

A body of mass 1 kg is moving with velocity of
(3î +4j) m/s. The kinetic energy possessed by it
will be
(1) 125 J
(2) 25 J
(3) 10.8 J
(4) 12.5 J

detailed explanation plzz ​

Answer 1

Explanation:

K.E = 1/2 ×mv²

= 1/2×1× (3î+4j)^2

=1/2 ×1× (3²+4²)

=1/2×1×(9+16)

=1/2×1×25

K.E = 12.5

Answer 2

The Kinetic Energy of the body is 12.5J. And option 'D' is correct.

Given:-

Mass of the body = 1kg

Velocity of the body = (3i + 4j)m/s

To Find:-

The Kinetic Energy of the body.

Solution:-

We can easily calculate the value of Kinetic energy of the body by using the following procedure.

As

Mass of the body (m) = 1kg

Velocity of the body (V) = (3i + 4j)m/s

Kinetic Energy of body (KE) =?

Now, magnitude of velocity = √3² + 4²

v = √9+16

v = √25

v = 5m/s

According to the formula,

$kinetic \: energy = \frac{1}{2} \times mass \times {(velocity)}^{2}$

$KE = \frac{1}{2} \times m \times {v}^{2}$

on putting the values, we get

$KE = \frac{1}{2} \times 1 \times {5}^{2}$

$KE = 25 \times \frac{1}{2}$

$KE = 12.5$

Hence, The Kinetic Energy of the body is 12.5J. And option 'D' is correct.

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