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2 years ago

14

(01.03 MC) Traveling at 65 miles per hour, how many minutes, rounded to the nearest whole number, does it take to drive 125 mile

s from San Diego to Malibu? 2 60 115 130

1 answer:

mariarad [96]2 years ago

4 0

It should take 115 minutes

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Initially, there are 40 grams of A and 50 grams of B, and for each gram of B, 2 grams of A is used. It is observed that 15 grams

hram777 [196]

Answer:

$X(16)=25.71grams$

Step-by-step explanation:

let $X(t)$ denote grams of $C$ formed in $t$ mins.

For $X grams$ of $C$ we have:

$\frac{2}{3}Xg$ of A and $\frac{1}{3}Xg$ of B

Amounts of A,B remaining at any given time is expressed as:

$40-\frac{2}{3}Xg$ of A and $50-\frac{1}{3}Xg$ of B

Rate at which C is formed satisfies:

$\frac{dX}{dt} \infty(40-\frac{2}{3}X)(50-\frac{1}{3}X)->\frac{dX}{dt}=k(90-X)\\\therefore \frac{dX}{(90-X)^2}=kdt->\int{\frac{dX}{(90-X)^2}} \, =\int {k} \, dt \\\therefore \frac{1}{90-X}=kt+c->90-X=\frac{1}{kt+c}\\\\X(t)=90-\frac{1}{kt+c}$

Apply the initial condition, $X(0)=0$ ,to the expression above

$0=90-\frac{1}{c} \ \ ->c=\frac{1}{90}\\\therefore\\X(t)=90-\frac{1}{kt+\frac{1}{90}} \ \ ->X(t)=90-\frac{90}{90kt+c}$

Now at $X(8)=15$ :

$15=90-\frac{90}{90\times 8k+1} \ ->75=\frac{90}{720k+1}\\k=0.0002778$

Substitute in X(t) to get

$X(t)=90-\frac{90}{0.0002778t\times 90+1}\\X(t)=90-\frac{90}{0.25t+1}\\But \ t=16\\\therefore X(t)=90-\frac{90}{0.025\times16+1}\\X(t)=25.71$

5 0

2 years ago

A 24.6 g marble sliding to the right at 62.0 cm/s overtakes and collides elastically with a 12.3 g marble moving in the same dir

Softa [21]

Answer:

Velocity of the 24.6 g marble is 31 cm/s.

Step-by-step explanation:

Given:

Marble 1:

Mass of the marble $(m_1)$ = 12.3 gm

Velocity of $m_1$ before collision $v_1_i$ = 15.5 cm/s

Velocity of $m_1$ after collision $v_1_f$ = 77.5 cm/s

Marble 2:

Mass of the marble $(m_2)$ = 24.6 gm

Velocity of $m_2$ before collision $v_2_i$ = 62 cm/s

Velocity of $m_2$ after collision $v_2_f$ = ?

From the law of conservation of momentum, we know that momentum before equals the momentum after :

So,

⇒ $P(i)=P(f)$

⇒ $(m_1\times v_1_i )+(m_2\times v_2_i) =(m_1\times v_1_f)+(m_2\times v_2_f)$

⇒ Plugging the values.

⇒ $(12.3\times 15.5) +(24.6\times 62)=(12.3\times 77.5)+(24.6\times v_2_f)$

⇒ $190.65+1525.2=953.25+24.6\times v_2_f$

⇒ $1715.85=953.25+24.6\times v_2_f$

⇒ $1715.85-953.25=24.6\times v_2_f$ ...subtracting both sides 953.25

⇒ $762.6=24.6\times v_2_f$

⇒ $\frac{762.6}{24.6}\ =v_2_f$ ...dividing both sides with 24.6

⇒ $31=v_2_f$

⇒ $v_2_f =31$ cm/s

The velocity of the 24.6 g marble after the collision is 31 cm/s and it will move opposite to of the 12.3 g marbles that is towards left.

6 0

3 years ago

A house cast a 10 foot shadow. A 5 foot boy castsa 4 foot shadow.

krok68 [10]

11 feet I think, hope this helps

7 0

2 years ago

Tree+snowman+tree=17

Karo-lina-s [1.5K]

Answer:

Step-by-step explanation:

Monke

8 0

2 years ago

Consider a group of kk people. Assume that each person's birthday is drawn uniformly at random from the 365 possibilities. (And

QveST [7]

Answer:

366

Step-by-step explanation:

Since there are 365 possible slots for people to have their birthday on, the worst case happens when all 365 people have different birthday. This means the 366th person would have their birthday falls on any of other’s birthday. Hence, kk must be at least 366.

6 0

2 years ago