Consider the upward direction of motion as positive and downward direction of motion as negative.
a = acceleration due to gravity in downward direction = - 9.8 
v₀ = initial velocity of rock in upward direction = ?
v = final velocity of rock at the highest point = 0 
t = time to reach the maximum height = 4.2 sec
Using the kinematics equation
v = v₀ + a t
inserting the values
0 = v₀ + (- 9.8) (4.2)
v₀ = 41.2 
answer:
an opaque object is one that doesn't let light pass through it. instead, it reflects or absorbs the light that strikes it.
explanation:
in this case, we see the material because of the transmitted light. therefore, the wavelength of the transmitted light determines the color that the object appears.
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I'm pretty sure what you are trying to ask for is radiative energy, light energy, and electronic energy
<span>Radiative since the microwave is releasing radiation </span>
<span>Light since there is light inside the microwave.</span>
Electronic since it is plugged in and uses electricity.
<span>You can also use sound, but I don't think every microwave makes sound. </span>
Answer B. the direction of force is the same