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Work is said to be done by a force actin...

Work is said to be done by a force acting on a body, provided the body is displaced actually in any direction except in a direction perpendicular to the direction of the force. Mathematically, `W=vec(F). vec(c)=Fs cos theta`, Whereas energy is capacity of a body to do the work, power is the rate at which the body can do the work.
`P=(W)/(t)=vec(F).(vec(s))/(t)=vec(F). vec(upsilon)`
Both, work and energy are measured in joule and power is measured in watt.
With the help of the comprehension given above, choose the most appropriate alternative for each of the following question `:`
A box is pushed through `4.0 m` across a floor offering `100N` resistance. Work done by the applied force is

A

`400J`

B

`-400 J`

C

`25 J`

D

`0.04 J`

Text Solution

Verified by Experts

The correct Answer is:
A
`W=F s cos theta = 100 xx 4 cos 0^(@)=400J`
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Knowledge Check

  • Work is said to be done by a force acting on a body, provided the body is displaced actually in ay direction except in a direction perpendicular to the direction of the force. Mathmatically, W=vec(F). vec(c)=Fs cos theta , Whereas eenrgy is capacity of a body to do the work, power is the rate at which the body can do the work. P=(W)/(t)=vec(F).(vec(s))/(t)=vec(F). vec(upsilon) Both, work and energy are measured in joule and power is measured in watt. With the help of the comprehension given above, choose the most appropriate alternative for each of the following question : In the above question, work done by the resisting force is

    A
    `400 J`
    B
    `-400 J`
    C
    zero
    D
    `-25 J`

  • Work is said to be done by a force acting on a body, provided the body is displaced actually in ay direction except in a direction perpendicular to the direction of the force. Mathmatically, W=vec(F). vec(c)=Fs cos theta , Whereas eenrgy is capacity of a body to do the work, power is the rate at which the body can do the work. P=(W)/(t)=vec(F).(vec(s))/(t)=vec(F). vec(upsilon) Both, work and energy are measured in joule and power is measured in watt. With the help of the comprehension given above, choose the most appropriate alternative for each of the following question : In the above question, work done by gravity is

    A
    `400 J`
    B
    `-400 J`
    C
    zero
    D
    `-25 J`

  • Work is said to be done by a force acting on a body, provided the body is displaced actually in any direction except in a direction perpendicular to the direction of the force. Mathematically, W=vec(F). vec(c)=Fs cos theta , Whereas energy is capacity of a body to do the work, power is the rate at which the body can do the work. P=(W)/(t)=vec(F).(vec(s))/(t)=vec(F). vec(upsilon) Both, work and energy are measured in joule and power is measured in watt. With the help of the comprehension given above, choose the most appropriate alternative for each of the following question : A truck draw a tractor of mass 1000 kg at a steady rate of 20 ms ^(-1) on a level road. The tension in the coupling is 2000N . Power spent on the tractor is

    A
    `40 W`
    B
    `20 W`
    C
    ` 20 kW`
    D
    `40 kW`