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3 years ago

Explain why you poured the ester into water before you identify the smell ?

1 answer:

3 0

You will pour the ester into water before you identify the smell because the smell is mixed with the smell of a carboxylic acid. with the use of the water the carboxylic acid will dissolved in it, while the ester will form a layer because it is not soluble in water, and you will smell it clearly

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2. A ball is thrown 45 m into the air. It takes the ball 5 s to hit the ground. What is the

koban [17]

Answer:

9m/s

Explanation:

45m÷5s=9m/s

Hope it helps!!!

6 0

3 years ago

Read 2 more answers

Describe the benefits and risks associated with nuclear energy.

Ulleksa [173]

Producing nuclear energy is far more environmentally friendly than burning fossil fuels. That is the main benefit.

The main risk is radiation. If the nuclear waste is not properly disposed of, it can leak radiation into the environment. Fortunately, this is not an issue since there are ways to deal with it. There is also the risk of a disaster like the Chernobyl incident, however that was mostly due to faulty reactor construction. However, reactors today are built to avoid such issues.

8 0

4 years ago

A heavy flywheel is accelerated (rotationally) by a motor that provides constant torque and therefore a constant angular acceler

ki77a [65]

Answer:

a) $t_1=\frac{w_1-w_o}{\alpha}=\frac{w_1}{\alpha}sec$

b) $\theta_1=\frac{w_1^2}{2\alpha}rad$

c) $t_2=\frac{\alpha t_1}{5\alpha}=\frac{t_1}{5}sec$

Explanation:

1) Basic concepts

Angular displacement is defined as the angle changed by an object. The units are rad/s.

Angular velocity is defined as the rate of change of angular displacement respect to the change of time, given by this formula:

$w=\frac{\Delat \theta}{\Delta t}$

Angular acceleration is the rate of change of the angular velocity respect to the time

$\alpha=\frac{dw}{dt}$

2) Part a

We can define some notation

$w_o=0\frac{rad}{s}$ ,represent the initial angular velocity of the wheel

$w_1=?\frac{rad}{s}$ , represent the final angular velocity of the wheel

$\alpha$ , represent the angular acceleration of the flywheel

$t_1$ time taken in order to reach the final angular velocity

So we can apply this formula from kinematics:

$w_1=w_o +\alpha t_1$

And solving for t1 we got:

$t_1=\frac{w_1-w_o}{\alpha}=\frac{w_1}{\alpha}sec$

3) Part b

We can use other formula from kinematics in order to find the angular displacement, on this case the following:

$\Delta \theta=wt+\frac{1}{2}\alpha t^2$

Replacing the values for our case we got:

$\Delta \theta=w_o t+\frac{1}{2}\alpha t_1^2$

And we can replace $t_1$ from the result for part a, like this:

$\theta_1-\theta_o=w_o t+\frac{1}{2}\alpha (\frac{w_1}{\alpha})^2$

Since $\theta_o=0$ and $w_o=0$ then we have:

$\theta_1=\frac{1}{2}\alpha \frac{w_1^2}{\alpha^2}$

And simplifying:

$\theta_1=\frac{w_1^2}{2\alpha}rad$

4) Part c

For this case we can assume that the angular acceleration in order to stop applied on the wheel is $\alpha_1 =-5\alpha \frac{rad}{s}$

We have an initial angular velocity $w_1$ , and since at the end stops we have that $w_2 =0$

Assuming that $t_2$ represent the time in order to stop the wheel, we cna use the following formula

$w_2 =w_1 +\alpha_1 t_2$

Since $w_2=0$ if we solve for $t_2$ we got

$t_2=\frac{0-w_1}{\alpha_1}=\frac{-w_1}{-5\alpha}$

And from part a) we can see that $w_1=\alpha t_1$ , and replacing into the last equation we got:

$t_2=\frac{\alpha t_1}{5\alpha}=\frac{t_1}{5}sec$

5 0

3 years ago

Estimate the number of Ping-Pong balls that can be packed into an average size room (without crushing them). Given that Ping-Pon

scoray [572]

Answer: 3,893,845.918 Ping-Pong balls

Explanation:

The volume of an average room is:

$V_{room}=(length)(width)(height)$ (1)

$V_{room}=(12 ft)(18 ft)(9 ft)=1944 ft^{3}$ (2)

Now let’s transform this $V_{room}$ to units of $cm^{3}$ , knowing $1 ft=30.48 cm$ :

$V_{room}=1944 ft^{3}\frac{{(30.48 cm)}^{3}}{1ft^{3}}=55,047,949.78 cm^{3}$ (3)

On the other hand, we have Ping-Pong balls with a radius $r=1.5 cm$ , and their volume is given by:

$V_{balls}=\frac{4}{3} \pi r^{3}$ (4)

$V_{balls}=\frac{4}{3} \pi (1.5 cm)^{3}$ (5)

$V_{balls}=14.137 cm^{3}$ (6)

Now, the number $n$ of Ping-Pong balls that can be packed into the room is:

$n=\frac{V_{room}}{V_{balls}}$ (7)

$n=\frac{55,047,949.78 cm^{3}}{14.137 cm^{3}}$ (8)

$n=3,893,845.918$ This is the number of Ping-Pong balls that can be packed into an average size room

7 0

3 years ago

Which object has a varying speed? a bird flying at 10 m/s for 10 seconds a car slowing from 60 m/s to 0 m/s a car traveling the

dolphi86 [110]

Answer:

The car slowing from 60 m/s to 0 m/s

Explanation:

The bird flying at 10m/s for 10 seconds will have the same speed for those 10 seconds. So we can say it doesn't have a varying speed (During those 10 seconds, we don't have any information about what happens later).

The fish moving at 2m/s for 5 minutes will have the same speed for those 5 minutes. So we can say it doesn't have a varying speed (During those 5 minutes, we don't have any information about what happens later).

The car traveling the speed limit, we know that his speed is the speed limit. It doesn't change.

The car slowing from 60 m/s to 0 m/s needs to change his speed in order to go from 60 m/s to 0 m/s. The speed will decrease progressively until the car completely stops.

8 0

3 years ago