Answer:
a = -7.29 m / s²
Explanation:
For this exercise we must use Newton's second law,
F -W = m a
Force is electrical force
F = k q₁ q₂ / r²
k q₁ q₂ / r² -mg = m a
indicate that the charge of the two spheres is equal
q₁ = q₂ = q
a = (k q² / r² - m g) / m
a = k q² / m r² - g
Let's reduce the magnitudes to the SI system
m = 0.19 g (1kg / 1000 g) = 1.9 10⁻⁴ kg
q1 = q2 = q = -23.0 nC (1C / 10⁹ nC) = -23.0 10⁻⁹ C
r = 10.0 cm (1m / 100cm) = 0.1000 m
let's calculate
a = 9 10⁹ (23.0 10⁻⁹)² / (0.1000² 1.9 10⁻⁴) - 9.8
a = -7.29 m / s²
The negative sign indicates that the direction of this acceleration is downward
Answer:
Lorsque l'on détend l'air son volume augmente et sa pression diminue. L'air qui est un mélange de gaz est compressible et expansible. – Lorsque l'on comprime l'air, son volume diminue et sa pression augmente. – Lorsque l'on détend l'air, son volume augmente et sa pression diminue.
Answer:
Explanation:
This is a problem based on time dilation , a theory given by Albert Einstein .
The formula of time dilation is as follows .
t₁ = 
t is time measured on the earth and t₁ is time measured by man on ship .
A ) Given t = 20 years , t₁ = ? v = .4c

=1.09 x 20
t₁= 21.82 years
B ) Given t = 5 years , t₁ = ? v = .2c

=1.02 x 5
t₁= 5.1 years
C ) Given t = 10 years , t₁ = ? v = .8c

=1.67 x 10
t₁= 16.7 years
D ) Given t = 10 years , t₁ = ? v = .4c

=1.09 x 10
t₁= 10.9 years
E ) Given t = 20 years , t₁ = ? v = .8c

=1.67 x 20
t₁= 33.4 years
Let the rescue boat starts at an angle theta with the North
now its velocity towards East is given as


now in some time "t" it will catch the boy
so we will have

also we have

now we have



by solving above we got
