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A soapbox derby is to be held on a frictionless hill with a 28 m vertical drop. The track is 300 m long. What is

ki77a [65]

Answer: -31039 J

Explanation:

5 0

3 years ago

Consider a particle with initial velocity v⃗ that has magnitude 12.0 m/s and is directed 60.0 degrees above the negative x axis.

lina2011 [118]

Answer:

-6.0 m/s, 10.4 m/s

Explanation:

To find the x- and y- components, we have to apply the formulas:

$v_x = v cos \theta$

$v_y = v sin \theta$

where

v = 12.0 m/s is the magnitude of the vector

$\theta$ is the angle between the direction of the vector and the positive x-axis

Here, the angle given is the angle above the negative x-axis; this means that the angle with respect to the positive x-axis is

$\theta=180^{\circ} - 60^{\circ} = 120^{\circ}$

So, the two components are:

$v_x = (12.0 m/s) cos 120^{\circ}=-6.0 m/s$

$v_y = (12.0 m/s) sin 120^{\circ}=10.4 m/s$

5 0

3 years ago

According to Newton’s law of universal gravitation, which statements are true? As we move to higher altitudes, the force of grav

Sliva [168]

According to Newton’s law of universal gravitation, as we move to higher altitudes, the force of gravity on us decreases and as we gain mass, the force of gravity on us increases both are the true statement.

<u>Explanation: </u>

Newton law of universal gravity extends gravity beyond the earth's surface. This gravity depends on the masses directly and inverse to the distance square between their centers.

$F=G \frac{M \times m}{r^{2}}$

Where,

F – Force, G – gravitational constant, M and m – masses in kg, r – distance in meters.

Since force is proportional to the masses of interacting objects. If the mass of any one object increases, gravity between them also gets increased. When moving to higher altitude, force decreases as the distance is inverse proportion to gravity.

4 0

3 years ago

Read 2 more answers

Which structures allow for the removal of wastes from the developing fetus?

castortr0y [4]

The fetus relies upon its mother as it develops. These are some of the things it needs:

<span>protection against knock and bumps, and temperature changes oxygen for respiration nutrients (food and water) </span>

The developing fetus also needs its waste substances removing.

The fetus is protected by the uterus and the amniotic fluid, a liquid contained in a bag called the amnion.

5 0

4 years ago

A cylinder of mass mm is free to slide in a vertical tube. The kinetic friction force between the cylinder and the walls of the

Zinaida [17]

Answer:

$y = \frac{-f +/- \sqrt{f^{2} +2kmg}}{k}$

Explanation:

Let y₀ be the initial position of the cylinder when the spring is attached and y its position when it is momentarily at rest.From work-kinetic energy principles, The work done by the spring force + work done by friction + work done by gravity = kinetic energy change of the cylinder

work done by the spring force = ¹/₂k(y₀² - y²)

work done by friction = - f(y - y₀)

work done by gravity = mg(y - y₀)

kinetic energy change of the cylinder = ¹/₂m(v₁² - v₀²)

So ¹/₂k(y₀² - y²) - f(y - y₀) + mg(y - y₀) = ¹/₂m(v₁² - v₀²)

Since the cylinder starts at rest, v₀ = 0. Also, when it is momentarily at rest, v₁ = 0

¹/₂k(y₀² - y²) - f(y - y₀) + mg(y - y₀) = ¹/₂m(0² - 0²)

¹/₂k(y₀² - y²) - f(y - y₀) + mg(y - y₀) = 0

¹/₂ky₀² + fy₀ - mgy₀ -¹/₂ky² - fy + mgy = 0

¹/₂ky₀² + fy₀ - mgy₀ = ¹/₂ky² + fy - mgy

Let y₀ = 0, then the left hand side of the equation equals zero. So,

0 = ¹/₂ky² + fy - mgy

¹/₂ky² + fy - mgy = 0

Using the quadratic formula

$y = \frac{-f +/- \sqrt{f^{2} - 4 X\frac{k}{2} X -mg}}{2 X \frac{k}{2} }\\ y = \frac{-f +/- \sqrt{f^{2} +2kmg}}{k}$

4 0

3 years ago