Answer:
The sound intensity that the other student measure, I₂ is expected to be;
A) 6.2 × 10⁻⁸ W/m²
Explanation:
The measure of sound intensity is given by the following formula;
Where;
I = The intensity
R = The radius
P = The power of the sound
Whereby we have;
The distance of the two people talking, R₁ = 3.0 m
The measure of the sound intensity, I₁ = 1.1 × 10⁻⁷ W/m² (from an online source)
The distance of the other student from the two people talking, R₂ = 4.0 m
Therefore, the estimate of the sound intensity, I₂, is given as follows;
I₂ = 6.1875 × 10⁻⁸ W/m²
∴ The sound intensity that the other student measure, I₂ ≈ 6.2 × 10⁻⁸ W/m²
It might be 144.2 m but i’m not for sure:)
Answer:
T = 190 N
Explanation:
When child is sitting on the swing then the weight of the child is vertically downwards
So it is
now a force of 100 N is acting on the swing in horizontal direction
so it is given as
now the net force is resultant force due to gravity and horizontal force
so it is given as
Answer:
The statement that refers to convection is Warm air rises and takes heat with it; eventually it cools and sinks
Explanation:
There are in general three modes of heat transfer: conduction, convection and radiation.
- In conduction, the heat transfers through contact
- In convection, the heat transfers through density difference
- In radiation, the heat transfers through wave motion
Consider first statement, 'Land and ocean absorb and re-emit heat from the sun'. Radiation is the only mode of heat transfer where there is no requirement for medium. The heat from sun to land and ocean has traveled by radiation. The process of re-emission also occurs in the same way.
Similarly in second statement the energy reflected of earth's atmosphere traveled by radiation and the last statement where sunlight travels through space without aid of fluids or solids refers to the process of radiation.
In third statement the warm air being less dense rises and takes heat with it; eventually it cools and thereby density increases which causes to sink. Here the movement of air is due to density difference, which concludes that this statement refers to convection
A spring is an object that can be deformed by a force and then return to its original shape after the force is removed.Springs come in a huge variety of different forms, but the simple metal coil spring is probably the most familiar. Springs are an essential part of almost all moderately complex mechanical devices; from ball-point pens to racing car engines.