<span>Answer:
skater x km/h
cyclist 20 faster x + 20 km/h
skater 30 km
cyclist 80 km
skater time = cyclist time
t=d/r
30 / x = 80 /( x + 20
cross multiply
30 ( x + 20 ) = 80 x
30 x + 600 = 80 x
30 x - 80 x = -600
-50 x = -600
/ -50
x = 12 km/h
12 km/h skater</span>
Answer:
v = 7.95 m/s
Explanation:
Given that,
Wavelength of a wave, 
Frequency of a wave, f = 15 Hz
We need to find the speed of the wave. The speed of a wave is given by :

So, the wave move with a speed of 7.95 m/s.
Answer:
More reactant forms.
Explanation:
Given reaction is,
⇒
per mole
This is an Exothermic Reaction,(ΔE=-57.3KJper mole)
We know the equilibrium point of all Exothermic reactions moves leftward and more reactant is formed at the equilibrium.
<u>Reason:</u>
As heat is being produced in the reaction the additional heat(57.3KJpermole) can be <u>thought of as a product</u> of the reaction.
So,if you increase the temperature ,you provide heat energy,
(in other words heat energy is given) and hence the concentration of the products increases.
So, with respect to LeChateliers Principle,
As the concentration of products is increased by external means,more of the reactants are produced at the equilibrium of the reaction.
Therefore amount of reactants increases as <u>more reactant forms.</u>
Answer: Scientists found evidence of Earths magnetic field reversal in rocks on the ocean floor at plate boundaries. These rocks have alternating polarity due to magnetization that occurred during their cooling period. Using radio metric dating, scientist estimate that reversals occur approximately every several hundred thousand years.
Explanation: