Which two quantities can be expressed using the same units?

An object is thrown vertically and has an upward velocity of 18 m/s when it reaches one

aalyn [17]

Answer:

20.78 m/s that we can approximate to option d (21 m/s)

Explanation:

The solution involves a lot of algebra and to be familiar with different convenient formulas for launching an object vertically under the action of gravity.

First you need to recall (or derive) the formula for the maximum height reached by an object with launches with initial velocity $v_0$ :

Maximum height = $\frac{{v_0}^2}{2g}$

Therefore one fourth of such height would be: $\frac{{v_0}^2}{8g}$

Second, find what would be the time needed to reach that height by solving for the time in the equation for the vertical position:

$y(t)=v_0*t-\frac{g}{2} t^2 \\\frac{{v_0}^2}{8g} = v_0*t-\frac{g}{2} t^2\\\frac{g}{2} t^2-v_0*t+\frac{{v_0}^2}{8g}=0$

And now, solve for t in the last equation using the quadratic formula to find the time needed for the object to reach that height (one fourth of the max height):

$t=\frac{v_0+/-\sqrt{{v_o}^2-4*\frac{g}{2}*\frac{{v_o}^2}{8g} } }{g} = \frac{v_0+/-\sqrt{{v_o}^2-\frac{{v_o}^2}{4} } }{g} =\frac{v_0+/-\sqrt{\frac{3{v_o}^2}{4} } }{g} = \\=\frac{v_0+/-v_0\sqrt{\frac{3}{4} } }{g} =\frac{v_0+/-v_0\frac{\sqrt{3}}{2} } {g}$

Next, use this expression for t in the equation for the velocity at any time t in the object's trajectory that comes from the definition of acceleration;

$v(t)=v_0-g*t$

Then for the time we just found, this new equation becomes:

$v=v_0-g(\frac{v_0+/-v_0\frac{\sqrt{3} }{2}}{g}) =v_0-v_0+/- v_0\frac{\sqrt{3} }{2} = +/- v_0 \frac{\sqrt{3} }{2}$

Now, using that the velocity at this height is 18 m/s, and solving for the unknown velocity $v_0$ , we get:

$v_0=\frac{18*2}{\sqrt{3} } =\frac{36}{\sqrt{3} }= 20.78\frac{m}{s}$

7 0

3 years ago

Agricultural waste used as fuel is an example of a _____. solar cell hydrogen fuel cell nonrenewable energy resource renewable e

kherson [118]

The answer is: Renewable energy resource.

The explanation for this completion exercise is shown below:

By definition, the Renewable energy is that the energy that is obtained from renewable resources. Renewable energy sources has taken on importance in recent years and plays an important role in the sustainable development of the planet.

Therefore, Agricultural waste used as fuel is an example of a Renewable energy resource, because you can obtain low emissions but high efficiency.

8 0

3 years ago

If a species experiences a helpful mutation, like camouflage, explain how that mutation would help the species to better survive

ExtremeBDS [4]

Answer:

A helpful mutation like camoflage would immensely help a species survive and flourish. The reason being the appliances of such a mutation. Camoflage is one of the most apllicable of abilities. It can be used as a defense mechanism, to hide in plain sight, it can be used offensively to avoid being seen while hunting and it can even be used as a form of communication between the species. All of these appliances would greatly benefit the species and would most definitely help it survive and flourish.

4 0

2 years ago

Distinguish between thermal energy, temperature, and heat. (BE SPECIFIC & use physics vocabulary)

xz_007 [3.2K]

Thermal energy can be defined as specific thermodynamic quantities as a part of energy transfer such as heat, which is a form of thermal energy flowing from hotter to colder objects. Temperature is a physical property of an object which specify whether the subject is hot or cold.

Explanation:

Difference between thermal energy, temperature and heat

Thermal Energy

Thermal energy is the total kinetic energy of molecules bundled up in the object. This energy is the heat exerted by the object which forms its temperature.

Temperature

In technical terms, temperature is the average kinetic energies measurement of molecules and atoms, present in an object. Simply, we can say, temperature defines how hot or how cold is a substance. Temperature relies on the kinetic energy of particles.

Heat

Transfer of thermal energy from a hotter to colder objects. Heat is different from temperature. Temperature is the mark to define how hot a substance is whereas, heat is the flow of thermal energy.

3 0

3 years ago

Someone help please i need to finish this

Tom [10]

Answer:

4th answer

Explanation:

The gradient of a distance-time graph gives the speed.

gradient = distance / time = speed

Here, the gradient is a constant till 30s. So it has travelled at a constant speed. It means it had not accelarated till 30s. and has stopped moving at 30s.

6 0

2 years ago