Answer:
The speed of her at the bottom is 24.035 m/s.
Explanation:
Given that,
Speed of cyclist = 12 m/s
Height = 30 m
Distance d = 450 m
Mass of cyclist and bicycle =70 kg
Drag force = 12 N
We need to calculate the speed at the bottom
Using conservation of energy
K.E+P.E=drag force+K.E+P.E
Potential energy is zero at the bottom.
K.E+P.E=drag force+K.E
Hence, The speed of her at the bottom is 24.035 m/s.
Iodine-131 has a half life of 8 days, so half of it is gone every 8 days.
10 grams of iodine-131 is left for 24 days.
At 8 days: 10/2=5 grams left
At 16 days: 5/2=2.5 grams left
At 24 days: 2.5/2=1.25 grams left.
**
Your mistake is that you stopped at 16 days.
The answer is d. Vacuum
Sound waves need a molecul to travel through. Gas , solid, annd liquid provide that medium.
But vacuum is just an empty space withour any moleculs in it.
Thats why in space, no one can hear you scream. Because it simply not physicsly possible
Unless you are a mutant....I don't think you would make it. I'm 5'8" and most people are 6'7" or less. It's bsically impossible to do. :)
I think an education guess for this one because he is thinking about what to guess probably.