Answer:
Electric field, 
Explanation:
It is given that,
Mass of sphere, m = 2.1 g = 0.0021 kg
Charge, 
We need to find the magnitude of electric field that balances the weight of a plastic spheres. So,

a = g



or

Hence, the magnitude of electric field that balances its weight is
. Hence, this is the required solution.
That's true.
And I'll go ya a better one:
If the object is moving or not moving, at a constant or changing speed, in a straight or curvy line, and the forces on it do not cancel out and add up to zero, the object will accelerate.
Sound is produced when something <span>vibrates.
</span>
Answer:
<u>Leather Shoes, Microphones, Candles</u>
<u>Explanation:</u>
Surprisingly, leather Shoes, Microphones, Candles were not mentioned in Stuff Matters a book written by Mark Miodownik which according to him explored "the marvelous things that shape our man-made world."
Answer:
ΔR = 9 s
Explanation:
To calculate the propagation of the uncertainty or absolute error, the variation with each parameter must be calculated and the but of the cases must be found, which is done by taking the absolute value
The given expression is R = 2A / B
the uncertainty is ΔR = |
| ΔA + |
| ΔB
we look for the derivatives
= 9 / B
= 9A (
)
we substitute
ΔR =
ΔA +
ΔB
the values are
ΔA = 2 s
ΔB = 3 s
ΔR =
2 +
3
ΔR = 1.636 + 7.14
ΔR = 8,776 s
the absolute error must be given with a significant figure
ΔR = 9 s