Q. 44.5( 2 Votes )
When the speed of a moving object is doubled, its :
A. acceleration is doubled
B. weight is doubled
C. kinetic energy is doubled
D. kinetic energy increases 4 times
Answer :
Kinetic energy KE of a body of mass m moving with velocity or speed v is given by the formula:
KE1 = 
mv12
If the speed of particle is doubled then
KE2 = 
mv22 where, v2 =
v1
Substituting the value of v2 in the formula,
KE2 = 
m (2v1)2
= 
(4 mv12)
KE2 = 4 KE1
So kinetic energy will become 4 times if the speed is doubled.
On other hand, acceleration depends on final as well as initial velocity, and here acceleration will be same.
Weight is independent of change in speed.
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