i know for sure the water one is correct with
A. Water is important to some organisms.
I'm 50/50 about the circulatory one BUT
A. carrying heat around the body.
that is your best bet
Answer:
Average speed=1.5 m/s
Frequency of pendulum=93.75Hz
Explanation:
We are given
Frequency, 
Average wavelength =
Speed of pendulum, 
Wavelength, 
We have to find the average speed and frequency of pendulum.
We know that
Speed,
Using the formula
Average speed,
Hence, the average speed =1.5m/s
Frequency, 
Using the formula


Hence, the frequency of a pendulum=93.75Hz
Answer:
B. Direction
Explanation:
Speed is a scalar quantity and doesn't keep track of direction : Velocity is a vector quantity and is direction aware.
Answer:
a) m = 993 g
b) E = 6.50 × 10¹⁴ J
Explanation:
atomic mass of hydrogen = 1.00794
4 hydrogen atom will make a helium atom = 4 × 1.00794 = 4.03176
we know atomic mass of helium = 4.002602
difference in the atomic mass of helium = 4.03176-4.002602 = 0.029158
fraction of mass lost =
= 0.00723
loss of mass for 1000 g = 1000 × 0.00723 = 7.23
a) mass of helium produced = 1000-7.23 = 993 g (approx.)
b) energy released in the process
E = m c²
E = 0.00723 × (3× 10⁸)²
E = 6.50 × 10¹⁴ J
Question :
If a body acquires a charge of -0.02 C, has it gained or lost electrons? Many?
Solution :
We know, charge gained is shown by negative sign.
Since, charged acquired is given as -0.02 C .
Therefore, it is body has gained electrons.
Now, number of electrons is given by :

Hence, this is the required solution.