Answer:
They can't hear an echo in small room because in it the sound can't be reflected back. For an echo of a sound to be heard,the minimum distance between the source of sound and the walls of the room should be 17.2 m.
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Answer:
Rust is a compound. What makes iron rust is its reaction with oxygen and moisture in the air.
Answer:
10 m/s
Explanation:
Momentum before collision = momentum after collision
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
(8 kg)(8 m/s) + (6 kg)(6 m/s) = (8 kg)(5 m/s) + (6 kg) v
64 kg m/s + 36 kg m/s = 40 kg m/s + (6 kg) v
60 kg m/s = (6 kg) v
v = 10 m/s
Answer:

Explanation:
Given that,
Pressure, P = 1 atm = 101325 Pa
Area of the square surface, A = 10² = 100 m²
We need to find the mass of vertical column of air. We know that, pressure is equal to the force acting per unit area. So,

So, the required mass of the vertical column of air is
.
Answer:
Explanation:
In wheel and axle. …with the system is the velocity ratio, or the ratio of the velocity (VF) with which the operator pulls the rope at F to the velocity at which the weight W is raised (VW). This ratio is equal to twice the radius of the large drum divided by the difference…