Answer:
They may not all be acurate
Explanation:
16. True (I think)
17.True
18.False (I think)
19.True
20.True
21.False
22.True
23. True
Answer:
a) v₀ = 39.83 v / s
, b) y = 111.94 m
Explanation:
a) Let's use the kinematic relations for this problem
v² = v₀² - 2 g y
The speed at the base of the cliff is 30 m / s, the height y = 31 m
v₀² = v² + 2 g y
v₀ =√ (30² + 2 9.8 31)
v₀ = 39.83 v / s
b) at the point of maximum height the speed is zero
0 = v₀² - 2 g (y –y0)
y = y₀ + v₀² / 2g
.y = 31 + 39.83²/2 9.8
y = 111.94 m
Sound waves in the air make tiny vibrations
Explanation:
spectral lines or signatures of elements depend on temperature, the temperature of the sun is about 5800 K.
at this temperature most calcium atoms are excited to higher energy states than hydrogen atoms and this means that calcium atoms are gonna have more signatures than the atoms of hydrogen.
the statement that the sun shows weak hyrogen lines and strong calcium line is wrong because at the sun's temperature most of the hydrogen atoms are in lower energy states while calcium atoms are in higher energy states hence calcium has more or ''strong'' lines than hydrogen.