Kinetic energy of an object is 25 j. Velocity is 5 m/s what will be its kinetic energy if velocity is doubles?

3 Answers
suryansh · Stefan V.
Feb 17, 2018

#"100 J"#

Explanation:

#"KE"=(1/2)*m*v^2#

Simple explanation :

Since the KE is proportional to velocity squared, if you increase the KE by a factor of #2#, you increase #v# by a factor of #2^2= 4#

Detailed explanation :

#25=0.5*m*(5^2)#

Find #m#:

#25=25m/2#

#m=2#

Hence the new KE:

#"KE"=0.5*2*10^2#

#"KE"=100 J#

Ayan · Stefan V.
Feb 17, 2018

The kinetic energy of body is #"100 J"#.

Explanation:

#"kinetic energy" =1/2 xx mxxv^2="25 J"#

#v = "5 m/s"#

Let the mass of body be #m#.

#1/2xxmxxv^2=25#

#mxx5^2=50#

#mxx 25=50#

#m=50/25#

or

#m = "2 kg"#

Now if velocity is doubled then

#v'=2 * v#

#v'=2×x5#

#v' = "10 m/s"#

The final kinetic energy #=1/2xxmxx(v')^2#

# =1/2x×2x×10^2#

# =1/2x×2x×100#

# =100J#

Nam D.
Feb 17, 2018

#100J#

Explanation:

We know that the equation for kinetic energy is

#KE=1/2mv^2#

Here, #v=5#, #KE=25#

#:.25=1/2*m*5^2#

#25=1/2*25*m#

#:.m=2#

So, the object's mass is #2kg#.

If the velocity doubles, then #v=5*2=10#, and then

#KE=1/2*10^2*2#

#KE=100J#

So, the object's kinetic energy will be #100J#.

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