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प्रश्न
Sleepers are used below the rails.
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उत्तर
Sleepers are laid below the rails to reduce pressure (force/area) on the ground.
∴ Sleepers increase the area.
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संबंधित प्रश्न
Name the factors affecting the turning effect of a body
State Newton's third law of motion.
The stone of hand flour grinder is provided with a handle near its rim. Give reason.
The moment of a force about axis depends ______.
Fig. shows a uniform meter scale weighing 100 N pivoted at its centre. Two weights of 500 N and 300 N are hung from the ruler as shown in fig.
(i) Calculate total clockwise and anticlockwise moments.
(ii) Calculate difference in clockwise moment and anticlockwise moment.
(iii) Calculate the distance from O where a 100 N weight should be suspended to balance the meter scale.
Define non-contact forces.
Assertion & Reasoning
- Assertion: The sum of the clockwise moments is equal to the sum of the anticlockwise moments.
- Reason: The principle of conservation of momentum is valid if the external force on the system is zero.
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- Give a reason for your answer in (a).
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- Calculate the distance of the person from the cliff.
- After moving a certain distance from the cliff, he fires the gun again, and this time the echo is heard 1.5 s later than the first. Calculate the distance that the person moved.
