Advertisements
Advertisements
प्रश्न
P, Q and R are three forces which act as shown in fig.
The point O lies in the same plane. Given, P = Q = R = 10N
(i) Which force has the least moment about O? Give a reason.
(ii)Which force has the greatest moment about O? Give a reason.
उत्तर
(i) Force 'R' has the least moment about 'O' because its perpendicular distance is least from 'O'.
(ii) Force 'P' has the maximum moment about 'O' because its perpendicular distance is maximum from 'O'.
APPEARS IN
संबंधित प्रश्न
Name a common device where a gear train is used
The energy of a body is its capacity to do .........
What are the two kinds of mechanical energy?
Differentiate between energy and power.
MULTIPLE CHOICE TYPE
In an electric cell which in use, the change in energy is from:
A boy weighing 25 kgf climbs up from the first floor at height 3 m above the ground to the third floor at height 9m above the ground. What will be the increase in his gravitational potential energy? (Take g = 10 N kg -1)
When is the work done by a force on a body : (a) positive, (b) negative, and (c) zero?
A max X goes to the top of a building by a vertical spiral staircase. Another man Y of the same mass goes to the top of the same building by a slanting ladder. Which of the two does more work against gravity and why?
Determine the amount of work done when an object is displaced at an angle of 30° with respect to the direction of the applied force.
Why is the work done on an object moving with uniform circular motion zero?
Complete the following sentences:
Kilowatt is the unit of ....... and kWh is the unit of
A boy of mass m climbs up a staircase of vertical height h.
- What is the work done by the boy against the force of gravity?
- What would have been the work done if he uses a lift in climbing the same vertical height?
Name the type of energy possessed by a
(i) stretched catapult (ii) hot iron
(iii) wound up clock
How fast should a boy weighting 30 kg run so that his kinetic energy is 375 joule?
Can two agents, doing the same work, have different power?
State larger units of power.
What do you understand by the term energy? Is energy a scalar or vector? How is the energy possessed by a body measured?
Mention whether work is done or not in the following activity.
| S. No | Activity | Work done or not done |
| 1. | Pushing the door | |
| 2. | Holding a doll | |
| 3. | Sitting in a bus | |
| 4. | Pushing a wall | |
| 5. | Digging soil |
A uniform chain of length 2 m is kept on a table such that a length of 60 cm hangs freely from the edge of the table. The total mass of the chain is 4 kg. What is the work done in pulling the entire chain on the table?
