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3 years ago

Which list correctly names the three types of galaxies?

Physics

2 answers:

goblinko [34]3 years ago

4 0

Answer:

B.irregular, spiral, elliptical

Explanation:

DedPeter [7]3 years ago

3 0

Answer:

3.irregular, spiral, elliptical

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A loaded 375 kg toboggan is traveling on smooth horizontal snow at 4.50 m/s when it suddenly comes to a rough region. The region

zmey [24]

Answer:

a) The average friction force exerted on the toboggan is 653.125 newtons, b) The rough region reduced the kinetic energy of the toboggan in 92.889 %, c) The speed of the toboggan is reduced in 73.333 %.

Explanation:

a) Given the existence of non-conservative forces (friction between toboggan and ground), the motion must be modelled by means of the Principle of Energy Conservation and the Work-Energy Theorem, since toboggan decrease its speed (associated with due to the action of friction. Changes in gravitational potential energy can be neglected due to the inclination of the ground. Then:

$K_{1} = K_{2} + W_{f}$

Where:

$K_{1}$ , $K_{2}$ are the initial and final translational kinetic energies of the tobbogan, measured in joules.

$W_{f}$ - Dissipated work due to friction, measured in joules.

By applying definitions of translation kinetic energy and work, the expression described above is now expanded and simplified:

$f\cdot \Delta s = \frac{1}{2}\cdot m \cdot (v_{1}^{2}-v_{2}^{2})$

Where:

$f$ - Friction force, measured in newtons.

$\Delta s$ - Distance travelled by the toboggan in the rough region, measured in meters.

$m$ - Mass of the toboggan, measured in kilograms.

$v_{1}$ , $v_{2}$ - Initial and final speed of the toboggan, measured in meters per second.

The friction force is cleared:

$f = \frac{m\cdot (v_{1}^{2}-v_{2}^{2})}{2\cdot \Delta s}$

If $m = 375\,kg$ , $v_{1} = 4.50\,\frac{m}{s}$ , $v_{2} = 1.20\,\frac{m}{s}$ and $\Delta s = 5.40 \,m$ , then:

$f = \frac{(375\,kg)\cdot \left[\left(4.50\,\frac{m}{s} \right)^{2}-\left(1.20\,\frac{m}{s}\right)^{2}\right]}{2\cdot (5.40\,m)}$

$f = 653.125\,N$

The average friction force exerted on the toboggan is 653.125 newtons.

b) The percentage lost by the kinetic energy of the tobbogan due to friction is given by the following expression, which is expanded and simplified afterwards:

$\% K_{loss} = \frac{K_{1}-K_{2}}{K_{1}}\times 100\,\%$

$\% K_{loss} = \left(1-\frac{K_{2}}{K_{1}} \right)\times 100\,\%$

$\% K_{loss} = \left(1-\frac{\frac{1}{2}\cdot m \cdot v_{2}^{2}}{\frac{1}{2}\cdot m \cdot v_{1}^{2}} \right)\times 100\,\%$

$\% K_{loss} = \left(1-\frac{v_{2}^{2}}{v_{1}^{2}} \right)\times 100\,\%$

$\%K_{loss} = \left[1-\left(\frac{v_{2}}{v_{1}}\right)^{2} \right]\times 100\,\%$

If $v_{1} = 4.50\,\frac{m}{s}$ and $v_{2} = 1.20\,\frac{m}{s}$ , then:

$\%K_{loss} = \left[1-\left(\frac{1.20\,\frac{m}{s} }{4.50\,\frac{m}{s} }\right)^{2} \right]\times 100\,\%$

$\%K_{loss} = 92.889\,\%$

The rough region reduced the kinetic energy of the toboggan in 92.889 %.

c) The percentage lost by the speed of the tobbogan due to friction is given by the following expression:

$\% v_{loss} = \frac{v_{1}-v_{2}}{v_{1}}\times 100\,\%$

$\% v_{loss} = \left(1-\frac{v_{2}}{v_{1}} \right)\times 100\,\%$

If $v_{1} = 4.50\,\frac{m}{s}$ and $v_{2} = 1.20\,\frac{m}{s}$ , then:

$\% v_{loss} = \left(1-\frac{1.20\,\frac{m}{s} }{4.50\,\frac{m}{s} } \right)\times 100\,\%$

$\%v_{loss} = 73.333\,\%$

The speed of the toboggan is reduced in 73.333 %.

5 0

3 years ago

2) If the initial velocity of an object is equal to a final velocity, what is the acceleration of the object?

Arlecino [84]

Answer:

The acceleration is 0.

Explanation:

The formula for acceleration is:

a = (v-u)/t

If v and u are equal, thus it would be 0 when subtracted, and anything divided by 0 is 0.

8 0

3 years ago

A car engine changes chemical potential energy into the blank energy of the moving car

kap26 [50]

<h3><u>Answer;</u></h3>

Kinetic energy

A car engine changes chemical potential energy into the <u>kinetic energy</u> of the moving car.

<h3><u>Explanation;</u></h3>

A car engine converts potential chemical energy stored in gasoline into thermal energy and then into kinetic mechanical energy.
When gasoline undergoes combustion it reacts with oxygen to produce carbon dioxide and water vapor.Gasoline is a mixture of octane and similar hydrocarbons and contains potential chemical energy.
The hot exhaust gases from the combustion of gasoline that are produced within the cylinder expand and exert pressure, moving the piston in the cylinder outward then inward as the gas is exhausted. Kinetic mechanical energy of the moving pistons is transferred to the drive shaft and eventually to the wheels, giving the car kinetic mechanical energy.

7 0

3 years ago

Consider a magnetic force acting on an electric charge in a uniform magnetic field. Which of the following statements are true?

CaHeK987 [17]

Answer:

Pushing magma up through the interior of earth

Explanation:

5 0

3 years ago

An environmentally-conscious student is breaking the rings from a six-pack drink holder before disposing of it. This reduces the

katrin2010 [14]

Answer: seen below.

Explanation:

Firstly we need to remember what exothermic reaction is in thermodynamics. exothermic reaction describes a process or reaction that releases energy from the system to its surroundings, usually in the form of heat, but also in a form of light, sound, or electricity.

In this scenario, due to the heating up nature noticed by the ring during breaking shows that energy is being released to the surrounding in the form of heat which suggest it being an exothermic reaction.

8 0

3 years ago