Question

the mass of an object is m and its velocity is v.if its kinetic energy is Ek,what will be the new kinetic energy of the object if its mass is doubled and its velocity is halved?​

Answer 1

Answer:

Given, velocityofobject,v=5ms

−1

;

kineticenergyofanobject,E

K

=25J

E

K

=

2

1

mv

2

or 25=

2

1

×m×(5)

2

or m=

25

50

=2kg

When the velocity triples,

E

K

=

2

1

mv

2

=

2

1

×2×(15)

2

=225J

Answer 2

Explanation:

we know,

K.E. =1/2mv^2

when mass is doubled and velocity is halved ,

K.E.' = 1/2(2m)(1/2v)^2

= 2*1/2m*1/4v^2

= 2*(1/4)*1/2mv^2

= 1/2*(1/2mv^2)

= 1/2* K.E.