Answer:
Your answer would be C, Radio waves.
Explanation:
It’s B. Sound travels faster through solids than liquids. Have you ever put your head on a desk, and tap the desk? That’s an example of it going faster through solids
Answer:
a)
Y0 = 0 m
Vy0 = 15 m/s
ay = -9.81 m/s^2
b) 7.71 m
c) 3.06 s
Explanation:
The knowns are that the initial vertical speed (at t = 0 s) is 15 m/s upwards. Also at that time the dolphin is coming out of the water, so its initial position is 0 m. And since we can safely assume this happens in Earth, the acceleration is the acceleration of gravity, which is 9.81 m/s^2 pointing downwards
Y(0) = 0 m
Vy(0) = 15 m/s
ay = -9.81 m/s^2 (negative because it points down)
Since acceleration is constant we can use the equation for uniformly accelerated movement:
Y(t) = Y0 + Vy0 * t + 1/2 * a * t^2
To find the highest point we do the first time derivative (this is the speed:
V(t) = Vy0 + a * t
We equate this to zero
0 = Vy0 + a * t
0 = 15 - 9.81 * t
15 = 9.81 * t
t = 0.654 s
At this time it will have a height of:
Y(0.654) = 0 + 15 * 0.654 - 1/2 * 9.81 * 0.654^2 = 7.71 m
The doplhin jumps and falls back into the water, when it falls again it position will be 0 again. So we can equate the position to zero to find how long it was in the air knowing that it started the jump at t = 0s.
0 = Y0 + Vy0 * t + 1/2 * a * t^2
0 = 0 + 15 * t - 1/2 * 9.81 t^2
0 = 15 * t - 4.9 * t^2
0 = t * (15 - 4.9 * t)
t1 = 0 This is the moment it jumped into the air
0 = 15 - 4.9 * t2
15 = 4.9 * t2
t2 = 3.06 s This is the moment when it falls again.
3.06 - 0 = 3.06 s
Answer: Their temperature decreases dramatically, but their luminosity increases only slightly.
Explanation: Edmentum answer
We will use the formula / equation to determined the time.
Distance = ½ * (vi + vf) * t
48100 = ½ * (26.3 + 41.9) * t
t = 48100 ÷ 34.1 = 1410.557185 seconds
We will use the formula / equation to determined the acceleration.
vf = vi + a * t
41.9 = 26.3 + a * 1410.557185
a = (41.9 – 26.3) ÷ 1410.557185 = 0.011059459 m/s^2
We will use the formula / equation to determined the acceleration.
vf^2 = vi^2 + 2 * a * d
41.9^1 = 26.3^2 + 2 * a * 48100
a = (41.9^2 – 26.3^2) ÷ 96200 = 0. 011059459 m/s^2
Since both answers are the same, I believe the acceleration is correct.
