Answer:
4.02 km/hr
Explanation:
5 km/hr = 1.39 m/s
The swimmer's speed relative to the ground must have the same direction as line AC.
The vertical component of the velocity is:
uᵧ = us cos 45
uᵧ = √2/2 us
The horizontal component of the velocity is:
uₓ = 1.39 − us sin 45
uₓ = 1.39 − √2/2 us
Writing a proportion:
uₓ / uᵧ = 121 / 159
(1.39 − √2/2 us) / (√2/2 us) = 121 / 159
Cross multiply and solve:
159 (1.39 − √2/2 us) = 121 (√2/2 us)
220.8 − 79.5√2 us = 60.5√2 us
220.8 = 140√2 us
us = 1.115
The swimmer's speed is 1.115 m/s, or 4.02 km/hr.
Answer:
a) F = 3.2 10⁻¹⁰ N
, b) v = 9.9 10⁷ m / s
Explanation:
a) The electric force is
F = q E
The electric field is related to the potential reference
V = E d
E = V / d
Let's replace
F = e V / d
Let's calculate
F = 1.6 10⁻¹⁹ 28 10³ / 1.4 10⁻²
F = 3.2 10⁻¹⁰ N
b) For this part we can use kinematics
v² = v₀ + 2 a d
v = √ 2 ad
Acceleration can be found with Newton's second law
e V / d = m a
a = e / m V / d
a = 1.6 10⁻¹⁹ / 9.1 10⁻³¹ 28 10³ / 1.4 10⁻²
a = 3,516 10⁻¹⁷ m / s²
Let's calculate the speed
v = √ (2 3,516 10¹⁷ 1.4 10⁻²)
v = √ (98,448 10¹⁴)
v = 9.9 10⁷ m / s
Answer:
Chemical composition, Temperature, Radial velocity, Size or diameter of the star, Rotation.
Explanation:
Elemental abundances are determined by analyzing the relative strengths of the absorption lines in the spectrum of a star.
The Spectral class to which the star belongs gives the information related to the temperature of the star. It is the spectral lines that determine the spectral class O B A F G K M are the spectral classes.
By measuring the wavelengths of the lines in the star's spectrum gives the radial velocity. Doppler shift is the method used to find the radial velocity.
A star can be classified as a giant or a dwarf . A giant star will have narrow width spectral lines whereas a dwarf star has wider spectral lines.
Broadening of the spectral lines will determine the star's rotation.
Well, 0.1 is actually less than 0.7, but I understand what you're asking.
The coefficient of friction describes the relationship between two surfaces
that are sliding by each other. The higher the coefficient of friction is, the
'rougher' the meeting is, and the harder it is for one to slide over the other.
A skate blade against ice has a very low coefficient of friction. Sandpaper
against blue jeans has a high coefficient of friction.
A higher coefficient of friction means that when one thing is sliding over
the other one, friction robs more energy from the motion. It's harder to
push one thing over the other one, and when you let go, the moving one
slows down and stops sooner.
Air resistance is actually an example of friction. It prevents falling things
from falling as fast as they would if there were no air. The coefficient of
friction when something moves through air is pretty low. If the same
object were trying to move through molasses or honey, the coefficient
of friction would be greater.
Friction robs energy, and turns it into heat. So, especially in machinery with
moving parts, we want to make the coefficient of friction between the moving parts
as small as possible. That's what the OIL in a car's engine is for.
Answer:
4.78 x 10^-11 J
Explanation:
A = 1.5 x 10^-4 m^2
d = 2 mm = 2 x 10^-3 m
V = 12 V
Let C be the capacitance of the capacitor
C = ε0 A / d
C = (8.854 x 10^-12 x 1.5 x 10^-4) / (2 x 10^-3)
C = 6.64 x 10^-13 F
Energy stored, U = 1/2 CV^2
U = 0.5 x 6.64 x 10^-13 x 12 x 12
U = 4.78 x 10^-11 J
