Answer:
4.35×10⁻⁴ m
Explanation:
(a)
From wave,
v = λf...................... Equation 1
Where v = speed of sound in air, λ = wavelength of sound, f = frequency of sound.
Make λ the subject of formula in equation 1
λ = v/f................. Equation 2
Given: v = 343, f = 3.45 MHz = 3.45×10⁶ Hz
Substitute into equation 2
λ = 343/(3.45×10⁶)
λ = 99.42×10⁻⁶ m
λ = 9.942×10⁻⁵ m
(b)
using,
v' = λ'f............... Equation 3
Where v' = speed of sound in tissue, λ' = wavelength of sound in tissue.
make λ' the subject of the equation
λ' = v'/f......................Equation 4
Given: v' = 1500 m/s, f = 3.45 MHz = 3.45×10⁶ Hz
Substitute into equation 4
λ' = 1500/(3.45×10⁶)
λ' = 434.783×10⁻⁶
λ' ≈ 4.35×10⁻⁴ m.
Explanation:
v=140 m/s
t=50s
u=0
change of velocity = v-u
140-0=140 m/s
for acceleration:
from Newton's first law of motion:
v=u+at
140=0+a50
50a=140
a=140/50
a=2.8 m/s²
When the core temperature rises, stars start burning helium to carbon. Hydrogen and helium are fused in a shell surrounding the core, raising the temperature.
The most prevalent method of generating energy in the cosmos is hydrogen fusion. The gravitational force is utilised to fuse hydrogen at the centres of our Sun and other stars, where it has a density more than 70 times greater than that of steel. Thus, all of the heat and light on earth comes from fusion. Helium is a chemical element with the atomic number 2 and the symbol He. The first member of the noble gas group in the periodic table, it is a colourless, odourless, tasteless, inert, monatomic gas that is not harmful.
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