The equation for potassium in water is:
K(s) + H20(l) --> H2(g) + K20(aq)
since a element and a compound are reacting, this is a single replacement reaction - which is a)
Explanation:
Given that,
Length of the spring, l = 50 cm
Mass, m = 330 g = 0.33 kg
(A) The mass is released and falls, stretching the spring by 28 cm before coming to rest at its lowest point. On applying second law of Newton at 14 cm below the lowest point we get :

(B) The amplitude of the oscillation is half of the total distance covered. So, amplitude is 14 cm.
(C) The frequency of the oscillation is given by :

Answer:
a
Explanation:
a is he answers . mass and density
Answer:
19320 kg/m³
Explanation:
density: This can be defined as the ratio of the mass of a body to its volume. The S.I unit of Density is kg/m³.
The formula of density is given as,
D = m/v ......................... Equation 1.
Where D = Density of the gold, m = mass of the gold, v = volume of the gold.
Note: From Archimedes's Principle, the piece of gold displace an amount of water that is equal to it's volume.
Amount of water displace = 27.2 - 25 = 2.2 mL.
Given: m = 42.504 g = 0.042504 kg, v = 2.2 mL = (2.2/10⁶) m³ = 0.0000022 m³
Substitute into equation 1
D = 0.042504/0.0000022
D = 19320 kg/m³
Hence the density of the piece of gold = 19320 kg/m³