KE=3070.625 J
Height = 3.686 m
<h3>Further explanation</h3>
mass of bike+rider=85 kg
velocity = 8.5 m/s

Conservation of energy :
(KE+PE)₁ (downhill) = (KE+PE)₂ (up the hill)
PE₁=0⇒h=0
KE₂=0⇒v=0(stop), so equation becomes :
KE₁=PE₂

Answer is: formula of hydrate is CoCl₂· 6H₂O -c<span>obalt(II) chloride hexahydrate
</span>m(CoCl₂· xH₂O) = 1,62 g.
m(CoCl₂) = 0,88 g.
n(CoCl₂) = m(CoCl₂) ÷ M(CoCl₂)
n(CoCl₂) = 0,88 g ÷ 130 g/mol
n(CoCl₂) = 0,0068 mol.
m(H₂O) = 1,62 g - 0,88 g.
m(H₂O) = 0,74 g.
n(H₂O) = m(H₂O) ÷ m(H₂O)
n(H₂O) = 0,74 g ÷ 18 g/mol
n(H₂O) = 0,041 mol.
n(CoCl₂) : n(H₂O) = 0,0068 mol : 0,041 mol.
n(CoCl₂) : n(H₂O) = 1 : 6.
The answer is force=6, time=3, so C is correct
The proper name for PCI6 is phosphorus hexachloride. Therefore it’s true