A block of mass 10 kg, moving in x direction with a constant speed of 10 $m s^{- 1}$ , is subjected to a retarding force F = 0.1 x J/m during its travel from x = 20 m to 30 m. It's final KE will be :

Q. A block of mass

10 k g

is moving in x-direction with a constant speed of

10 m / s

. It is subjected to a retarding force

F = 0.1 x J / m

during its travel from

x = 20 m

x = 30 m .

Its final kinetic energy will be :

Q. A block of mass

10 k g

is moving in x-direction with constant speed of

10 m / s

. It is subjected to a retarding force

F = 0.1 x

joule/metre during its travel from

x = 20 m

x = 30 m

. Its final K.E will be:

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A block of mass 10 kg, moving in x direction with a constant speed of 10ms−1, is subjected to a retarding force F=0.1xJ/m during its travel from x=−20 m to 30 m. Its final KE will be

The correct option is C 475 JWork done is equal to change in KE.Work done W=∫30−20Fdx=∫30−200.1xdx=0.12[x2]30−20=0.12(900−400)=2512m(v21−v22)=25⇒12×10×(102−v22)=25KEfinal=12×10×100−25=500−25=475J

A block of mass $10$ kg, moving in x direction with a constant speed of $10 m s^{- 1}$ , is subjected to a retarding force $F = 0.1 x J / m$ during its travel from $x = - 20 m$ to $30 m$ . Its final KE will be