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3 years ago

Tommy was walking at a rate of 4

1 answer:

8 0

A positive acceleration indicates that the object sped up. This means that if you compare the first speed to the second, the second speed should be higher.

A negative acceleration indicates that the object has slowed down. This means that if you compare the first speed to the second, the second speed should be lower.

If an acceleration is 0, it means that it neither slowed down nor sped up.

Now let us analyze your problem by listing down the speed and the time:

At noon: 4 mi/hr
12:30 : 6 mi/hr
2:30 : 2 mi/hr

From noon to 12:30, you will notice that there is an increase in speed. This means that Tommy had a positive acceleration. (Rules out D.)

From 12:30 to 2:30, there is a decrease in speed. This would indicate that Tommy had a negative acceleration. (Rules out C.)

No speed was the same, so acceleration was never 0. (Rules out A.)

From the assumptions above, we can now deduce that the answer is B.

You might be interested in

Identify the variables in the investigation: An investigation was done with an electromagnetic system made from a battery and wi

kondaur [170]

Answer:

Independent: sizes of nails

Dependent: number of paper clips

Controlled: Battery, wire and type of nails

Explanation:

An independent variable is a variable which when changes does not the effect the results of the experiment. It does not depends upon the dependent variable.

A dependent variable is defined as a variable which is affected when the independent variable is changed by the researcher or the experimenter. It depends greatly upon the independent variable.

While a controlled variable is that variable whose value is not changed in an experiment. It contains all the constants.

In the context,

the independent variable are : sizes of nails

the dependent variables are : number of paper clips

the Controlled variables are: Battery, wire and type of nails

8 0

2 years ago

Genes are located in which part of a cell?

ddd [48]

Answer:A

Explanation:

7 0

3 years ago

Suppose the half-life is 9.0 s for a first order reaction and the reactant concentration is 0.0741 M 50.7 s after the reaction s

bazaltina [42]

<u>Answer:</u> The time taken by the reaction is 84.5 seconds

<u>Explanation:</u>

The equation used to calculate half life for first order kinetics:

$k=\frac{0.693}{t_{1/2}}$

where,

$t_{1/2}$ = half-life of the reaction = 9.0 s

k = rate constant = ?

Putting values in above equation, we get:

$k=\frac{0.693}{9}=0.077s^{-1}$

Rate law expression for first order kinetics is given by the equation:

$k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}$ ......(1)

where,

k = rate constant = $0.077s^{-1}$

t = time taken for decay process = 50.7 sec

$[A_o]$ = initial amount of the reactant = ?

[A] = amount left after decay process = 0.0741 M

Putting values in equation 1, we get:

$0.077=\frac{2.303}{50.7}\log\frac{[A_o]}{0.0741}$

$[A_o]=3.67M$

Now, calculating the time taken by using equation 1:

$[A]=0.0055M$

$k=0.077s^{-1}$

$[A_o]=3.67M$

Putting values in equation 1, we get:

$0.077=\frac{2.303}{t}\log\frac{3.67}{0.0055}\\\\t=84.5s$

Hence, the time taken by the reaction is 84.5 seconds

6 0

3 years ago

6. (1 point) What is the correct formula for sodium sulfate? *

Deffense [45]

6) Na2 SO4
7)nonmetallic elements
10)mass
11) mole
* sorry I didn't know Q. 8/9

4 0

3 years ago

Read 2 more answers

Select the compound that is most likely to increase the solubility of ZnSe when added to water.NaCnMgBr2NaClKClO4

vlada-n [284]

Answer:

NaCl.

Explanation:

In the solution, ZnSe ionizes to $Zn^2^+$ and $Se^2^-$ . Following reaction represents the ionization of ZnSe in solution -

$ZnSe$ ⇄ $Zn^2^+ + Se^2^-$

As we want to increase the solubility of ZnSe, we must decrease the concentration of dissociated ions so that the reaction continues to forward direction.

If we add NaCl to this solution, then we have $Na^+$ and $Cl^-$ in the solution which will be formed by the ionization of NaCl.

Now, $Zn^2^+$ in the solution will react with two $Cl^-$ ions to form $ZnCl_2$ as follows -

$Zn^2^++2Cl^-$ ⇄ $ZnCl_2$

Due to this reaction the concentration of $Zn^2^+$ will decrease in the solution and more ZnSe can be soluble in the solution.

6 0

2 years ago