2.1 kg of sodium bicarbonate is equal to the 2.1 x 10¹² ng of sample. Option D is correct.
Mass is the quantity of the substance in the body or object. The SI unit of mass is Kilogram.
There are other units of measure,
- Milligram: 1 g is equal to the

- Micro-gram: 1 g is equal to

- Nano-gram: 1 g is is equal to
First convert kg to gram,
Since, 1 Kg = 1000 g
2.1 kg = grams of sample
So,
Do the cross multiplication,

Now, convert 2100 g to nano-grams
Since, 1 g = 1 x 10⁹ ng
2100 g = ng of sample
So,
Do the cross multiplication,

Therefore, 2.1 kg of sodium bicarbonate is equal to the 2.1 x 10¹² ng of sample.
To know more about Mass units,
brainly.com/question/489186
The vector c is the answer
Answer choice A
Lol what i think i’ve heard of that story
Answer:
C. 21 Joules
Explanation:
We apply the formula to calculate the potential energy (Ep):
Ep=m*g*h
Where:
Ep : potential energy in Joules (J)
m :mass in kilograms (kg)
g acceleration due to gravity (m/s²)
h: height in meters (m)
Calculation of the height (h)
Ep = m*g*h
7 = (1.5 )*(9.8) *(h
)
7 = (14.7) (h
)
h = 7 / (14.7)
h= 0.476 m
Gravitational potential energy of the second object
Ep = m*g*h
Ep = (4.5 )*(9.8) *(0.476
)
Ep = (4.5 )*(9.8) *(0.476
)
Ep = 21 J