Question

A stone of mass 500g is thrown vertically upwards with a velocity of 15m/s . Calculate the kenitic energy​

Answer 1

Answer:

Kinetic Energy, K.E=0.5×m×v

2

K.E=0.5×0.5×15×15=56.25J

As it has 56.25 J at the initial point as total energy, at some point X,Potential Energy(P.E.) is maximum.

Total energy=P.E.+K.E.

56.25=P.E.+K.E.

As energy is conserved total energy at point X also must be 40 J.

For P.E to be maximum K.E. must be zero.

Hence P.E.=56.25J

We can come to the conclusion that potential energy will have the maximum value at maximum height.

Answer 2

Given :

mass of the stone, m = 500g = 0.5kg

velocity of the stone, v = 15m/s

To find :

the kenitic energy of the stone

Solution :

Kinetic energy is directly proportional to the mass of the object and to the square of its velocity. It is scalar quantity .i.e.,

${ \leadsto{ \bf{K.E = \dfrac{1}{2}mv^2}}}$

${ \leadsto{ \bf{K.E = \dfrac{1}{2}(0.5)(15)^2}}}$

${ \leadsto{ \bf{K.E = 56.25 \: J}}}$

thus, the kenitic energy of the stone is 56.25J

Remember !

SI unit of kenitic energy is Joules (J)