Answer:
The height reached is 20m, The time taken to reach 20m is 2 seconds
Explanation:
Observing the equations of motion we can see that the following equation will be most helpful for this question.
![v^{2} = u^{2} + 2as](https://tex.z-dn.net/?f=v%5E%7B2%7D%20%3D%20u%5E%7B2%7D%20%2B%202as)
We are given initial velocity, u
We know that the stone will stop at its maximum height, so final velocity, v
Acceleration, a
And we are looking for the displacement (height reached), s
Substitute the values we are given into the equation
![0^{2} = 20^{2} + 2(10)s](https://tex.z-dn.net/?f=0%5E%7B2%7D%20%3D%2020%5E%7B2%7D%20%2B%202%2810%29s)
Rearrange for s
![0^{2} -20^{2} =20s](https://tex.z-dn.net/?f=0%5E%7B2%7D%20-20%5E%7B2%7D%20%3D20s)
![-400=20s](https://tex.z-dn.net/?f=-400%3D20s)
![\frac{-400}{20} =s](https://tex.z-dn.net/?f=%5Cfrac%7B-400%7D%7B20%7D%20%3Ds)
s = -20 (The negative is just showing direction, it can be ignored for now)
The height reached is 20m
Use a different equation to find the time taken
![s = vt - \frac{1}{2} at^{2}](https://tex.z-dn.net/?f=s%20%3D%20vt%20-%20%5Cfrac%7B1%7D%7B2%7D%20at%5E%7B2%7D)
Substitute in the values we have
![-20=(0)t - \frac{1}{2} (10)t^{2}](https://tex.z-dn.net/?f=-20%3D%280%29t%20-%20%5Cfrac%7B1%7D%7B2%7D%20%2810%29t%5E%7B2%7D)
Rearrange for t
![-20 =0 -5 t^{2}](https://tex.z-dn.net/?f=-20%20%3D0%20-5%20t%5E%7B2%7D)
![\frac{-20}{-5} =t^{2}](https://tex.z-dn.net/?f=%5Cfrac%7B-20%7D%7B-5%7D%20%3Dt%5E%7B2%7D)
![4 = t^{2}](https://tex.z-dn.net/?f=4%20%3D%20t%5E%7B2%7D)
t = 2s
The time taken to reach 20m is 2 seconds
Answer:
Options B, A, D, C
Explanation:
When a scientists, let's say Roberto wonders if the presence of other elements also affects the color of a flame, he can decide to prove this through a study. Therefore, in chemistry class, Roberto sees that traces of lithium makes a flame appear bright red. Subsequently, Roberto designs an experiment to test flame color in the presence of different elements and finally Roberto's friend tells him the color of a flame cannot be changed, but Roberto is still unsure.
Answer:
47.4 m
Explanation:
When an object is thrown upward, it rises up, it reaches its maximum height, and then it goes down. The time at which it reaches its maximum height is half the total time of flight.
In this case, the time of flight is 6.22 s, so the time the ball takes to reach the maximum height is
![t=\frac{6.22}{2}=3.11 s](https://tex.z-dn.net/?f=t%3D%5Cfrac%7B6.22%7D%7B2%7D%3D3.11%20s)
Now we consider only the downward motion of the ball: it is a free fall motion, so we can find the vertical displacement by using the suvat equation
![s=ut+\frac{1}{2}gt^2](https://tex.z-dn.net/?f=s%3Dut%2B%5Cfrac%7B1%7D%7B2%7Dgt%5E2)
where
s is the vertical displacement
u = 0 is the initial velocity
t = 3.11 s is the time
is the acceleration of gravity (taking downward as positive direction)
Solving the formula, we find
![s=\frac{1}{2}(9.8)(3.11)^2=47.4 m](https://tex.z-dn.net/?f=s%3D%5Cfrac%7B1%7D%7B2%7D%289.8%29%283.11%29%5E2%3D47.4%20m)
Answer:
I think that when a book hits the ground its potential energy converts into kinetic energy and then kinetic energy is transformed into sound and heat energy.
Explanation: