Answer:
This is because the speed of a wave is determined by the medium through which it is passing. When light speeds up as it passes from one material to another, the angle of refraction is bigger than the angle of incidence. For example, this happens when light passes from water to air or from glass to water ❤
The velocity of penguin as he ends where he started was 0 m/s.
<h3>What is displacement?</h3>
Displacement is the length of straight line joining the initial and final position of the body.
Given is a penguin who waddled 8 m uphill before sliding back down to its friends in 2 seconds.
We know that the velocity is the rate of change of displacement with respect to time. Mathematically -
v = dx/dt
dx = v dt
∫dx = ∫v dt
Δx = vΔt
v = Δx/Δt
Now, the displacement of the penguin will be = Δx = 8 - 8 = 0
Then, its velocity will be -
v = 0/Δt = 0
Therefore, the velocity of penguin as he ends where he started was 0 m/s.
To solve more questions on kinematics, visit the link below-
brainly.com/question/27200847
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Answer:
F = 7.2N
Explanation:
The resultant of two forces acting at some angle is given by using the vector addition as given below
F =√F1^2+F2^2+2F1F2cosθ
Where F1 = 6N and F2 = 8N
θ = 240°
Substituting the values into the equation above
F = √ 6^2+8^2+ 2(6×8)cos240
F =√ 36+64+96cos240
F = √ 100+96 ×-0.5
F = √ 100-48
F = √ 52
F = 7.211
F = 7.2N
Answer:
3 times louder
Explanation:
The Loudness in decibel Db L = 10㏒(I/I₀) where I = sound intensity level and I₀ = threshold of hearing = 10⁻¹² W/m².
Now, for Jessica, I₁ = sound intensity level of Jessica's music = 10⁻⁹
and I₂ = sound intensity level of Braylee's music = 10⁻³
So, substituting the variables into the equation, we have
L₁ = 10㏒(I₁/I₀)
L₁ = 10㏒(10⁻⁹/10⁻¹²)
L₁ = 10㏒(10³)
L₁ = 3 × 10㏒10
L₁ = 30㏒10
L₁ = 30 dB
Now, for Braylee, I₂ = sound intensity level of Braylee's music = 10⁻³
So, substituting the variables into the equation, we have
L₂ = 10㏒(I₁/I₀)
L₂ = 10㏒(10⁻³/10⁻¹²)
L₂ = 10㏒(10⁹)
L₂ = 9 × 10㏒10
L₂ =90㏒10
L₂ = 90 dB
So, the number of times Braylee's music is louder than Jessica's music is L₂/L₁ = 90 dB/30 dB = 3
So, Braylee's music is 3 times louder than Jessica's music
Answer:
v = -1.8t+36
20 seconds
360 m
40 seconds
36 m/s
The object speed will increase when it is coming down from its highest height.
Explanation:
Differentiating with respect to time we get
a) Velocity of the object after t seconds is v = -1.8t+36
At the highest point v will be 0
b) The object will reach the highest point after 20 seconds
c) Highest point the object will reach is 360 m
d) Time taken to strike the ground would be 20+20 = 40 seconds
![[tex]v=u+at\\\Rightarrow v=0+0.9\times 2\times 20\\\Rightarrow v=36\ m/s](https://tex.z-dn.net/?f=%5Btex%5Dv%3Du%2Bat%5C%5C%5CRightarrow%20v%3D0%2B0.9%5Ctimes%202%5Ctimes%2020%5C%5C%5CRightarrow%20v%3D36%5C%20m%2Fs)
Acceleration will be taken as positive because the object is going down. Hence, the sign changes. 2 is multiplied because the expression is given in the form of 
e) The velocity with which the object strikes the ground will be 36 m/s
f) The speed will increase when the object has gone up and for 20 seconds and falls down for 20 seconds. The object speed will increase when it is coming down from its highest height.
