Well, the thing is: we don't really know, as we don't even know how many species there are on earth.
If we take a look at the estimates of <span>World Wide Fund for Nature, an organization that works toward combating species extinction, their estimates vary from 200 to 100 000 - but a probable number is 20 000 (d). </span>
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Answer:3.67 m/s
Explanation:
mass of block(m)=2 kg
Velocity of block=6 m/s
spring constant(k)=2 KN/m
Spring compression x=15 cm
Conserving Energy
energy lost by block =Gain in potential energy in spring

![2\left [ 6^2-v_2^2\right ]=2\times 10^3\times \left [ 0.15\right ]^2](https://tex.z-dn.net/?f=2%5Cleft%20%5B%206%5E2-v_2%5E2%5Cright%20%5D%3D2%5Ctimes%2010%5E3%5Ctimes%20%5Cleft%20%5B%200.15%5Cright%20%5D%5E2)

Answer:
y = 4 Sin (2πt)
Explanation:
Amplitude, A = 4
frequency, f = 1
Wave function is given by
y = A sinωt
where, ω is angular frequency
ω = 2 π f = 2 π x 1 = 2π
So, the desired wave function
y = 4 Sin (2πt)
Answer: The speed necessary for the electron to have this energy is 466462 m/s
Explanation:
Kinetic energy is the energy posessed by an object by virtue of its motion.

K.E= kinetic energy = 
m= mass of an electron = 
v= velocity of object = ?
Putting in the values in the equation:


The speed necessary for the electron to have this energy is 466462 m/s