Answer:
The speed of the stone before it hit the river 3.00 sec later. Let v is the velocity at that instant is 45 m/s.
Explanation:
Given that, a child threw a stone straight down off a high bridge.
Initial velocity of the stone, u = 15 m/s
We need to find the speed of the stone before it hit the river 3.00 sec later. Let v is the velocity at that instant. When it come down, it is moving under the action of gravity. Using equation of motion as :
So, the speed of the stone before it hit the river 3.00 sec later. Let v is the velocity at that instant is 45 m/s.
Answer:
the tension of the rope is 34.95 N
Explanation:
Given;
length of the rope, L = 3 m
mass of the rope, m = 0.105 kg
frequency of the wave, f = 40 Hz
wavelength of the wave, λ = 0.79 m
Let the tension of the rope = T
The speed of the wave is given as;
Therefore, the tension of the rope is 34.95 N
Let's call the constant acceleration a.
At a time t, its speed will thus be v(t)=a*t+v0 where v0 is its initial speed, here 10 m/s. Hence v(t)=a*t+10.
From there we can deduce the position P(t)=a*t^2/2+10t+p0 where p0 is the initial position, here 0.
Hence P(t)=a*t^2/2+10t
Let's call T the time at which it's at 50 m/s, we know that P(T)=225m and that v(T)=50 m/s hence a*T+10=50 thus a=40/T and P(T)=(40/2+10)T=30T
Hence T=225/30=7.5
It took 7.5 seconds
C) refract
Explanation:
When light passes from air into water, the light waves will bend or they refract and the pencil will appear to be broken.
In normal space, light travels along a straight path with no alteration of the path along which it travels.
- When light crosses the boundary from a denser to a less dense medium, it is refracted.
- Refraction implies that the angle of the light is bent.
- This is because the new medium causes the light rays to slow down compared to the speed it was coming forth with.
Learn more:
Refraction brainly.com/question/12370040
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