Answer:
(a) 1.257 x 10^5 J
(b) 1.456 Watt
Explanation:
Volume of blood, v = 7500 L = 7.5 m^3
Height, h = 1.63 m
density of blood, d = 1.05 x 10^3 kg/m^3
(a) work done = m x g x h
W = v x d x g x h = 7.5 x 1.05 x 1000 x 9.8 x 1.63 = 1.257 x 10^5 J
(b) time = 1 day = 24 x 60 x 60 s = 86400 seconds
Power = Work / time = 1.257 x 10^5 / 86400 = 1.456 Watt
Answer:
Dark matter does not affect our view, humans can see through them.
Explanation:
They do not affect our view because we can see right through the (weakly interacting) dark matter, as they do not interact or interfere with electromagnetic force.
Dark matter are often invisible substances and are difficult to spot because they don't absorb or reflect light.
Answer:

Explanation:
initially the merry go round is at rest
after 6.73 s the merry go round will accelerates to 20 rpm
so final angular speed is given as



so final tangential speed is given as


now average acceleration of the girl is given as



<h2>The temperature of the air is 66.8° C</h2>
Explanation:
From the Newton's velocity of sound relationship , the velocity of sound is directly proportional to the square root of temperature .
In this case The velocity of sound = frequency x wavelength
= 798 x 0.48 = 383 m/sec
Suppose the temperature at this time = T K
Thus 383 ∝
I
The velocity of sound is 329 m/s at 273 K ( given )
Thus 329 ∝
II
Dividing I by II , we have
= 
or
= 1.25
and T = 339.8 K = 66.8° C
I think this is TRUE. Ph is calculating the acidic acids in water. And you need to know the concentration of hydronium ions. Hope this helped !