Mechanical advantage of a block and tackle system increases on increasing the number of pulleys. Give reason

Mechanical advantage of the block and tackle system of pulleys increases because the number of strands balancing the load increases.

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What is loudness of a sound?

Loudness of a sound is the characteristic of a sound which depend on the intensity of energy it carries. Intensity of a sound is the amount of energy passing through a surface area of one square metre held perpendicular per sec. Intensity depends on square of amplitude of the wave passing. Hence we can say Loudness is directly proportional to the square of Amplitude. If amplitude is doubled, loudness becomes four times. Loudness depends on distance of source from the listener. Loudness depends on resonance also.

Freezer compartment of a refrigerator is placed at its top portion. Why?

Cold air from the freezing compartment settles down owing to its higher density and keeps the temperature of the contents below it low.

NEWTON'S THIRD LAW

The law states that "to every action there is an equal and opposite reaction and these forces act on different bodies" Examples 1. When a rocket is launched, the burnt gases are expelled down from the rocket body. Here action is on gases by the rocket body. Hence the gases exert an equal an opposite force on the rocket body in the upward direction. This is the reaction force. With this force rocket moves in upward direction. ACTION...on the gases by the Rocket body. REACTION..On the rocket by the burnt gases. 2. When a gun fires bullets, action is on the bullets by the gun and reaction on the gun by the bullets. Gun recoils back due to the reaction. ACTION: On the bullets by the gun.. REACTION...on the gun by the bullets

PHYSICS

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