Answer:
34 m/s
Explanation:
Potential energy at top = kinetic energy at bottom + work done by friction
PE = KE + W
mgh = ½ mv² + Fd
mg (d sin θ) = ½ mv² + Fd
Solving for v:
½ mv² = mg (d sin θ) − Fd
mv² = 2mg (d sin θ) − 2Fd
v² = 2g (d sin θ) − 2Fd/m
v = √(2g (d sin θ) − 2Fd/m)
Given g = 9.8 m/s², d = 150 m, θ = 28°, F = 50 N, and m = 65 kg:
v = √(2 (9.8 m/s²) (150 m sin 28°) − 2 (50 N) (150 m) / (65 kg))
v = 33.9 m/s
Rounded to two significant figures, her velocity at the bottom of the hill is 34 m/s.
<span>A deviation between observed and model values that was much larger than the observation uncertainties led Kepler to abandon circular orbits and his discovery that planetary orbits are ellipses</span>
Answer: a
Explanation: It is the only answer that is precipitation
The work done on the sail is 600 J
Explanation:
The work done to lift the sail is equal to the gain in gravitational potential energy of the sail, therefore is:
where
m is the mass of the sail
g is the acceleration of gravity
(mg) is the weight of the sail
is the change in height of the sail
In this problem we have
mg = 150 N (weight)
Substituting, we find the work done:
Learn more about work:
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First, we need to find the number of protons, which is the total mass divided by the mass of one proton:
protons
Then, the total charge is the number of protons times the charge of a single proton: