Advertisements
Advertisements
Question
A body, when acted upon by a force of 20 kgf, gets displaced by 1 m. Calculate the work done by the force, when the displacement is
- in the direction of force,
- at an angle of 60° with the force, and
- normal to the force. (g = 10 N kg-1)
Advertisements
Solution
F = 20 kgf = 20 × 10 N = 200 N
Displacement S = 1 m
Work done
- When displacement is in the direction of force
W = F × S
W = 200 × 1 = 200 J - When displacement is at an angle of 60°
W = F.S cos 60°
= 200 × 1 × `1/2`
= 100 J - When displacement is normal to the direction of force
W = F.S cos 90°
= 200 × 1 × 0
= 0 (Zero)
APPEARS IN
RELATED QUESTIONS
How is the work done by a force measured when the force is in the direction of displacement?
A force F acts on a body and displaces it by a distance S in a direction at an angle θ with the direction of force.
Write the expression for the work done by the force.
A body is acted upon by a force. State two conditions when the work done is zero.
Choose one or more correct alternatives.
While dragging or lifting an object, negative work is done by ______.
- the applied force
- gravitational force
- frictional force
- reaction force
From the groups B and C, choose the proper words, for each of the words in group A.
| A | B | C |
| Work | Newton | erg |
| Force | Metre | cm |
| Displacement | Joule | dyne |
Explain the following concept in your own words with everyday examples:
Work
Explain the following concept in your own words with everyday examples:
Displacement
A cart with mass 20 kg went 50 m in a straight line on a plain and smooth road when a force of 2 N was applied to it. How much work was done by the force?
What should be the angle between the direction of force and the direction of displacement, for work to be negative?
A force 'F' moves a load from A to C as shown in the figure below. For the calculation of the work done, which of these lengths would you use as the displacement?
