Question:
Mateo drew the field lines around the ends of two bar magnets but forgot to label the direction of the lines with arrows. In which direction should an arrow at position 1 point?
left
right
up
down
Answer:
The correct answer is
Left
Explanation:
Magnetic circuits describe the path of a magnetic flux. In the same way electricity follows a complete closed circuit, the path of a magnetic flux is also a complete and closed circuit which leaves from the N pole, migrates through the air and reenters the magnet through the S pole through which it passes back into the magnet to come to the N pole again.
As such the magnetic field lines emanate from the N pole which is on he right to the S pole which is on the left. Hence the arrow should point in the left direction.
Answer:
The 15 ⁰C measured at this altitude is above the standard temperature for the altitude.
Explanation:
The standard temperature at sea level is 15 degrees Celsius. It decreases about 2 degrees C (or 3.5 degrees F) per 1,000 feet of altitude above sea level.
235 meters is equal to 771 feet.
Using the formula below, we can estimate temperature loss due to this change in altitude, that is 771 feet above sea level.
temperature loss = (3.5 x Change in altitude)/1000ft
temperature loss = (3.5 x 771ft)/1000ft = 2.7⁰F, (32 -2.7 = 29.3 ⁰F)
this is equivalent to 1.5⁰C temperature loss.
Thus, the standard temperature of the engineering quadrangle at 235 meters above sea level is 13.5 ⁰C.
Therefore, the 15 ⁰C measured at this altitude is above the standard temperature for the altitude.
Answer:
34.6 m/s
Explanation:
Since there are no external forces acting on the system, the total momentum of the kids+sled system must be conserved, so we can write:
where:
is the mass of kid A
is the mass of kid B
is the mass of kid C
u = 19.8 m/s is the initial velocity of the system
v is the final velocity of the system, after kid A jumped off it
Here we have ignored the mass of the sled since it is not given.
Therefore, by solving the equation for v, we find the new velocity of the sled:
the resistance that one surface or object encounters when moving over another.
"a lubrication system that reduces friction"
synonyms: abrasion, abrading, rubbing, chafing, grating, rasping, scraping, excoriation, grinding, gnawing, eating away, wearing away/down; More
the action of one surface or object rubbing against another.
"the friction of braking"
Friction is an important force because it is a force that affects motion. This force exerted by the surface of an object when another object moves against it is the result of molecular attractions between the objects' surfaces, and works in the direction opposite to the direction of the motion.
Answer:
v₀ = 13.9 10³ m / s
Explanation:
Let's analyze this exercise we can use the basic kinematics relationships to love the initial velocity and the acceleration we can look for from Newton's second law where force is gravitational attraction.
F = m a
G m M / x² = m dv / dt = m dv/dx dx/dt
G M / x² = dv/dx v
GM dx / x² = v dv
We integrate
v² / 2 = GM (-1 / x)
We evaluate between the lower limits where x = Re = 6.37 10⁶m and the velocity v = vo and the upper limit x = 2.50 10⁸m with a velocity of v = 8.50 10³ m/s
½ ((8.5 10³)² - v₀²) = GM (-1 /(2.50 10⁸) + 1 / (6.37 10⁶))
72.25 10⁶ - v₀² = 2 G M (+0.4 10⁻⁸ - 1.57 10⁻⁷)
72.25 10⁶ - v₀² = 2 6.63 10⁻¹¹ 5.98 10²⁴ (-15.3 10⁻⁸)
72.25 10⁶ - v₀² = -1.213 10⁸
v₀² = 72.25 10⁶ + 1,213 10⁸
v₀² = 193.6 10⁶
v₀ = 13.9 10³ m / s