Question

If kinetic energy of a man of mass 40 kg while running is 500 J, then his velocity is ​

Answer 1

Explanation:

Given, mass of the man, m=60kg

Kinetic energy of the man, E

k

=750J

If v is the velocity of the man, then

E

k

=

2

1

mv

2

or v=

m

2E

k

=

60

2×750

=5m/s

Answer 2

Answer:

The correct answer is that if kinetic energy of a man of mass 40 kg while running is 500 J, then his velocity is 5m/s.

Explanation:

Definition of Kinetic energy -

• As we know, the energy an object has as a result of motion is known as kinetic energy in physics.
• It is described as the effort required to move a mass-determined body from rest to the indicated velocity.
• The body keeps the kinetic energy it acquired throughout its acceleration unless its speed changes.

Definition of velocity -

• The rate at which an object's position changes when observed from a specific point of view and when measured against a specific unit of time is known as its velocity.

Now the formula to be used in this question is ,

KE = 1/2 (mv²)

Given :

Mass of the man = 40kg

Kinetic energy of the man = 500J

To find :

Velocity = ?

Solution :

The relation combining velocity and mass and kinetic energy is KE = 1/2 (mv²)

By modifying the formula according to our need, we get :

2KE = mv²

2KE/ m = v²

v = √(2KE/ m)

Therefore by substituting the values given to us in the question, we get :

v =√[ (2 x 500) / 40 ]

v = √25

v = 5 m/s

Therefore according to our above calculation the answer is that if kinetic energy of a man of mass 40 kg while running is 500 J, then his velocity is 5m/s.

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