D is the best answer. C is somewhat true, increasing the amplitude of a wave will make it louder, but loudness depends on the listener. To a person hard of hearing, a given amplitude will sound quieter than for a normal hearing person.
Answer:
136 N
Explanation:
Pressure on large piston = pressure on small piston
F₁ / A₁ = F₂ / A₂
1700 N / 1.5 m² = F / 0.12 m²
F = 136 N
Answer:
B.)Angular momentum is always conserved
Explanation:
Angular momentum is given by:
where
m is the mass of the object
v is its speed
r is the distance between the object and the centre of its circular trajectory
In absence of external torques, angular momentum is always conserved. That means that for the spinning star, if its radius r decreases (because it shrinks), in order for L (the angular momentum) to be conserved, the speed (v) must increases, therefore the spinning star speeds up.
So, the correct choice is
B.)Angular momentum is always conserved
Explanation:
to provide a stable base load of energy
The amount of work that has been done on the projectile by air friction is 7,569.2 J.
<h3>
Work done by air friction on the projectile</h3>
The work done by air friction on the projectile is calculated as follows;
W = ΔK.E
W = ¹/₂mvf² - ¹/₂mv₀²
where;
- vf is the final velocity = 85 m/s
- v₀ is the initial vertical velocity = 100 x sin(20) = 34.2 m/s
W = ¹/₂m(vf² - v₀²)
W = ¹/₂ x 2.5 (85² - 34.2²)
W = 7,569.2 J
Thus, the amount of work that has been done on the projectile by air friction is 7,569.2 J.
Learn more about work done here: brainly.com/question/8119756
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