Answer:
a) 6.95 m/s
b) 1.42 seconds
Explanation:
t = Time taken
u = Initial velocity
v = Final velocity
s = Displacement
a = Acceleration due to gravity = 9.81 m/s²
![v^2-u^2=2as\\\Rightarrow -u^2=2as-v^2\\\Rightarrow -u^2=2\times -9.81\times 2.46-0^2\\\Rightarrow u=\sqrt{2\times 9.81\times 2.46}\\\Rightarrow u=6.95\ m/s](https://tex.z-dn.net/?f=v%5E2-u%5E2%3D2as%5C%5C%5CRightarrow%20-u%5E2%3D2as-v%5E2%5C%5C%5CRightarrow%20-u%5E2%3D2%5Ctimes%20-9.81%5Ctimes%202.46-0%5E2%5C%5C%5CRightarrow%20u%3D%5Csqrt%7B2%5Ctimes%209.81%5Ctimes%202.46%7D%5C%5C%5CRightarrow%20u%3D6.95%5C%20m%2Fs)
a) The vertical speed when it leaves the ground. is 6.95 m/s
![v=u+at\\\Rightarrow t=\frac{v-u}{a}\\\Rightarrow t=\frac{0-6.95}{-9.81}\\\Rightarrow t=0.71\ s](https://tex.z-dn.net/?f=v%3Du%2Bat%5C%5C%5CRightarrow%20t%3D%5Cfrac%7Bv-u%7D%7Ba%7D%5C%5C%5CRightarrow%20t%3D%5Cfrac%7B0-6.95%7D%7B-9.81%7D%5C%5C%5CRightarrow%20t%3D0.71%5C%20s)
Time taken to reach the maximum height is 0.71 seconds
![s=ut+\frac{1}{2}at^2\\\Rightarrow 2.46=0t+\frac{1}{2}\times 9.81\times t^2\\\Rightarrow t=\sqrt{\frac{2.46\times 2}{9.81}}\\\Rightarrow t=0.71\ s](https://tex.z-dn.net/?f=s%3Dut%2B%5Cfrac%7B1%7D%7B2%7Dat%5E2%5C%5C%5CRightarrow%202.46%3D0t%2B%5Cfrac%7B1%7D%7B2%7D%5Ctimes%209.81%5Ctimes%20t%5E2%5C%5C%5CRightarrow%20t%3D%5Csqrt%7B%5Cfrac%7B2.46%5Ctimes%202%7D%7B9.81%7D%7D%5C%5C%5CRightarrow%20t%3D0.71%5C%20s)
Time taken to reach the ground from the maximum height is 0.71 seconds
b) Time it stayed in the air is 0.71+0.71 = 1.42 seconds
The answer is D, the amount of energy stays the same.
Answer:
To develop a molecular clock, you need to find which of the following?
a sequence of molecules
the rate at which changes occur in a type of molecule
how much total change has occurred in a type of molecule from two different species
how many molecules a species has
Explanation:
s;s;
Answer:
You cheated on a test, and you know it was the wrong thing to do. According to the psychoanalytic theory, what helped you know this?
The id controlled your biological response and made you sweaty because you were scared of getting caught.
The superego acted as your moral conscience; you just knew that it wasn't right to cheat.
The ego made you feel guilty as a defense mechanism. both B and C
Explanation:
the answer is both B,C