Answer:
Explanation:18kt alloy contains
i) 75% of gold
rhogold=19.3g/cm^3
=75/100×19.3
=14.475g/cm^3
ii) 16% of silver
rhosilver=10.5g/cm^3
=16/100×10.5
=1.68g/cm^3
iii) 9% of copper
rhocopper =8.90g/cm^3
=9/100×8.9
=0.801g/cm^3
Overall density of 18kt gold
=(0.801+1.68+14.475)g/cm^3
=16.956g/cm^3
=17g/cm^3 to 3s.f
Answer: a boy jumping down
Answer:the one with the smaller radius has the highest centripetal force
Explanation:
Answer:
The distance between the two successive crests of the wave is 360m
Explanation:
Wavelength is defined as the property of wave in which the distance between identical points between two successive waves are calculated
Wavelength is referred to as the <em>distance between two successive crests or troughs</em>
<em>Given that:</em>
speed = 72.0 m/s
time = 5 seconds
Using the formula
C = fλ
Where C = speed, f = freequency and λ = wavelength
F = 1 / time
F = 1/5
F = 0.2Hz
From the fomula C = fλ
make λ the subject of the formula
λ = C / f
λ = 72/0.2
<em>λ = 360m</em>
<u>Answer:</u>
<em>The moon doesn’t change shape on its own.</em>
<u>Explanation:</u>
Shapes of moon that we observe is based on the different perspectives of view from the earth and position of moon with respect to the sun. The changes arise due to the rotation of earth on its own axis as well as the revolution of moon on its orbit. The moon doesn’t have any light of its own.
It just reflects off the light from the sun. Due to tidal locking phenomenon one face of the moon permanently faces the sun. Because of the changes in position of moon with respect to the sun the moon is lighted up variably giving rise to various phases like new moon, full moon, crescent etc.
