Home
Class 11
PHYSICS
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`
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • WORK, ENERGY AND POWER

    PRADEEP|Exercise Integer Type Questions|9 Videos

  • WORK, ENERGY AND POWER

    PRADEEP|Exercise Assertion-Reason Type Questions|24 Videos

  • WORK, ENERGY AND POWER

    PRADEEP|Exercise JEE (Main and Advanced)|82 Videos

  • THERMODYNAMICS

    PRADEEP|Exercise Assertion- Reason Type Questions|19 Videos

Similar Questions

Explore conceptually related problems

A force acts perpendicular to the direction of motion of a body. What is work done?

Work done by a force is zero when a body gets displaced along a direction ……….. to the direction of applied force .

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`

    • Similar Questions

    Explore conceptually related problems

    On applying a force (vec(F) = 3hat(i) - 6hat(j) + 4hat(k)) N on a body , the body is dispalced through along negative direction of X - axis is 2 m . Calculate the work done by this force .

    The velocity of a body moving in a straight line is increased by applying a constant force F, for some distance in the direction of the motion. Prove that the increase in the kinetic energy of the body is equal to the work done by the force on the body.

    A body is at rest under the action of three forces, two of which are vec(F)_(1)= 4hat(i), vec(F)_(2)= 6hat(j) , the third force is

    Given that a force F acts on a body for time t_(1) and displaces the body by vec d . In which of the following cases the velocity of the body must increases ?

    If the direction of position vector vec r is towards south and direciton of force vector vec F is towards east, then the direction of torque vector vec tau is

    Home
    Profile