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प्रश्न
Complete the following sentences:
1 J = ........ Erg.
उत्तर
1 J = 107 Erg.
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संबंधित प्रश्न
A boy has to lift a load of mass 50 kg to a height of 1 m. (a) what effort is required if he lifts it directly? Take g = 10 N kg-1 (b) If the boy can exert a maximum effort of 250 N, so he uses an inclined plane to lift the load up. What should be the minimum length of the plank used by him?
A fixed pulley is driven by a 100 kg mass falling at a rate of 8.0 m in 4.0s. It lifts a load of 75.0 kgf. Calculate the power input to the pulley taking the force of gravity on 1 kg as 10 N.
In a block and tackle system consisting of 3 pulleys, a load of 75 kgf is raised with an effort of 25 kgf. Find:
- the mechanical advantage,
- velocity ratio and
- efficiency.
A block and tackle system has 5 pulleys. If an effort 0f 1000 N is needed in the downward direction to raise a load of 4500 N, calculate:
- the mechanical advantage
- the velocity ratio, and
- the efficiency of the system.
In following figure, shows a system of four pulleys, The upper two pulleys are fixed and the lower two are movable.
- Draw a string around the pulleys. Also show the place and direction in which the effort if applied.
- What is the velocity ratio of the system?
- How are load and effort of the pulley system related?
- What assumption do you make in arriving at your answer in part (c)?
In following figure, shows a block and tackle system of pulleys used to lift a load.
- How many strands of tackle are supporting the load?
- Draw arrows to represent tension T in each strand.
- What is the mechanical advantage of the system?
- When load is pulled up by a distance 1 m, how far does the effort end move?
- How much effort is needed to lift a load of 100 N?
- What will be it's V.R. if the weight of the movable block is doubled?
A block and tackle system has the velocity ratio 3. Draw a labelled diagram of the system indicating the points of application and the directions of load L and effort E. A man can exert a pull of 200 kgf. What is the maximum load he can raise with this pulley system is its efficiency is 60%?
A single fixed pulley and a movable pulley both are separately used to lift a load of 50 kgf to the same height. Compare the efforts applied in an ideal situation.
A woman draws water from a well using a fixed pulley. The mass of the bucket and water together is 60 kg. The force applied by the woman is 70 N. Calculate the mechanical advantage. [Take g = 10 m/s2].
The mechanical advantage of a machine is 5 and its efficiency is 80%. It is used to lift a load of 200 kgf to a height of 20 m. Calculate:
(i) The effort required, and
(ii) The work done on the machine (g = 10 ms−2).
