Question

velocity of an object of mass 200 gram changes from 36 kilometre per hour to 25 metre per second when a constant force is applied on it calculate the work done by the force​

Answer 1

Answer:

mass of the object = 200g = 0.2 kg

*1 kg = 1000g

initial velocity( u )= 36km/hr =10 m/sec

final velocity ( v ) = 25 m/sec

According to Work energy theorem:

Work done by a moving body is always equal to change in its kinetic energy.

Work = K.E.¹ - K.E.²

Work = 0.5mv² - 0.5mu²

Work = 0.5 ×0.2× (25)² - 0.5 × 0.2 × (10)²

Work = 52.5 Joule

Answer 2

» Velocity of an object of mass 200 gram changes from 36 kilometre per hour to 25 metre per second when a constant force is applied on it.

Here...

Mass (m) = 200 g

=> $\frac{200}{1000}$ = 0.2 kg

Initial velocity (u) = 36 km/hr

=> 36 × $\frac{5}{18}$ = 10 m/s

Final velocity (v) = 25 m/s

_____________ [GIVEN]

• We have to calculate the work done by the force.

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Work done in moving a body is equal to change in it's kinetic energy.. means kinetic energy of final - kinetic energy of initial.

Work done = $K.E_{1}$ - $K.E_{2}$

=> $\dfrac{1}{2}$ mv² - $\dfrac{1}{2}$ mu²

=> $\dfrac{1}{2}$ × 0.2 [(25)² - (10)²]

=> 0.1 (625 - 100)

=> 0.1 × 525

=> 52.5 J

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Work done by the force is 52.5 J.

__________ [ANSWER]

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