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प्रश्न
Calculate the decrease in the kinetic energy of a moving body if its velocity reduces to half of the initial velocity.
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उत्तर
We know for kinetic energy, body must have velocity
Let initial velocity = v
Also, Kinetic energy is equal to
K.E. = `1/2"m""v"^2`
given velocity decreased to half, so new velocity v'
v' = `"v"/2`
= K.Enew = `1/2 "m" xx ("v"/2)2`
= K.Enew = `1/2 "m" "v"^2/4`
∴ K.Enew = `("m""v"^2)/8`
Now, as asked, we need to find the decrease
Δ K.E = `("m""v"^2)/2 - ("m""v"^2)/8`
Δ K.E = `3/4"m""v"^2`
Kinetic energy will decrease by `3/4`th of initial kinetic energy.
संबंधित प्रश्न
Give one relevant example for the following transformation of energy :
Electrical energy to light energy.
Name the type of energy (kinetic energy K or potential energy U) possessed in the given case:
An arrow shot out of a bow.
Select the renewable and non-renewable sources of energy from the following:
Diesel
Explain the principle of generating electricity from hydro energy.
MULTIPLE CHOICE TYPE:
The ultimate source of energy is:
(a) wood
(b) wind
(c) water
(d) sun
What do you understand by mechanical energy?
What kind of energy is possessed in a situation when?
A horse running along a level road
State the energy changes which take place when:
A stone projected vertically upwards, returns back to the thrower.
State the energy changes which take place when:
Water freezes in the freezing chamber of a fridge.
Give one example when:
Potential energy changes to electric energy.
