Suppose r(t) = (et cos t)i + (et sin t)j. Show that the angle between r and a never changes. What is the angle?

Answers

Answer 1

Answer:

Angle = Ф = [tex]cos^{-1}[/tex](0) = 0

Hence, it is proved that angle between position vector r and acceleration vector a = 0 and is it never changes.

Step-by-step explanation:

Given vector r(t) = [tex]e^{t}cost i + e^{t}sint j[/tex]

As we know that,

velocity vector = v = [tex]\frac{dr}{dt}[/tex]

Implies that

velocity vector = [tex](e^{t} cost - e^{t} sint)i + (e^{t} sint - e^{t}cost )j[/tex]

As acceleration is velocity over time so:

acceleration vector = a = [tex]\frac{dv}{dt}[/tex]

Implies that

vector a =

[tex](e^{t}cost - e^{t}sint - e^{t}sint - e^{t}cost )i + ( e^{t}sint + e^{t}cost + e^{t}cost - e^{t}sint )j[/tex]

vector a = [tex](-2e^{t}sint) i + ( 2e^{t}cost)j[/tex]

Now scalar product of position vector r and acceleration vector a:

r. a = [tex]<e^{t}cost, e^{t}sint> . <-2e^{t}sint, 2e^{t}cost>\\[/tex]

r.a = [tex]-2e^{2t}sintcost + 2e^{2t}sintcost[/tex]

r.a = 0

Now, for angle between position vector r and acceleration vector a is given by:

cosФ = [tex]\frac{r.a}{|r|.|a|}[/tex] = [tex]\frac{0}{|r|.|a|} = 0[/tex]

Ф = [tex]cos^{-1}[/tex](0) = 0

Hence, it is proved that angle between position vector r and acceleration vector a = 0 and is it never changes.


Related Questions

During a ten-minute science experiment, the temperature of a substance decreases at a constant rate.
​Which graph represents this situation?
A.
B.
C.
D.

Answers

The answer is A bc it has the graph decreasing at a constant speed.

Help I don’t get this

Answers

Answer:

550 pounds of lettuce and cheese combined.

Step-by-step explanation:

ok so

1/10 of 5,000

and

1/100 of 5,000

(1/10)5,000

it is 500 pounds of cheese

now for 1/100

(1/100)5000

it is 50 pounds of lettuce

500+50=550

Hope this helps.

What is the solution to the system of equations below?
y = 2x + 8
3(-2x + y)=12

Answers

Step-by-step explanation:

There is inconsistency in the given statement and no solution

Explanation:

y

=

2

x

+

2

x

y

=

8

,

Eqn (1)

3

(

2

x

+

y

)

=

12

6

x

+

3

y

=

12

2

x

y

=

4

Eqn (2)

It may be seen, L H S of equations (1) & (2) are same but not R H S.

Hence there is inconsistency in the given statement and no solution

eremy constructed this solid by combining two rectangular prisms and a square pyramid.

A rectangular prism with a length of 6 meters, width of 14 meters, and height of 2 meters. A rectangular prism with a length of 5 meters, width of 8 meters, and height of 3 meters. A square pyramid with a base of 6 meters by 6 meters and triangular sides with a height of 7 meters.


What is the surface area of this figure?

_____________ square meters
320
322
368
386

Answers

368 square meters is the answer

A lawyer has an annual income of $240,000. The income tax that doctor has to pay is 6%. What is the amount of income tax in dollars and cents that the lawyer has to pay?

Answers

Answer:

Step-by-step explanation:

240,000*6=14,400 dollars

the dr has to be taxes 14,400 dollars

what is w/3=7 the w/3 is a fraction​

Answers

Answer:

w=21

since 3 x 7 = 21

I hope I'm right

yall know what to do so imma let yall do your thing
Solve for x: 2x – y = (3/4)x + 6.

Answers

Answer:

x=4y/5 + 24/5

Step-by-step explanation:

x = 4y/5 + 24/5

20 cHarActErs blAh bLah BlaH

Mrs.Bailey had 15 pieces of candy. She gave away some candy and has 3 pieces left. What is the percent decrease of candy?

Answers

Answer:

12

Step-by-step explanation:

subtract 15 away from 3 and you have 12 so that how Mrs. Bailey has 3 pieces of candy left

Answer:

80% decrease

Step-by-step explanation:

Find out how much percent each candy is worth:

100/15 = 6.67%

Find out how many pieces she gave away:

15 - 3 = 12

Multiply the pieces gave away by the percent per piece:

12 x 6.67 = 80.04

Round to the nearest whole number.

When using a calculator for 100/15 and then multiply by 12 you get exactly 80.

Michael needs to pick up a set of notes from his friend's house. He has two friends who have the notes
available, Friend A or Friend B. He wants to go to the nearest friend.

HELL ASAP!

Answers

Friend A because it’s the closest

please help meeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee and you get prizeee big prize

Answers

Answer:

22/7

Step-by-step explanation:

2 3/4=11/4

(11/4)/(7/8)

(11/4)(8/7)

(11/1)(2/7)

=22/7

The answer is 22/7.

Solve each equation by factoring. 5a^2-2a-47=0

A. I/2,-6
B. 7/5 , -1
C. 1/5 ,-7
D.-4/7,-1

Answers

Answer:

a = -2.872 and 3.272

Step-by-step explanation:

Given the equation 5a^2-2a-47=0

Using the general formula;

a = 2±√2²-4(5)(-47)/2(5)

a = 2±√4+940/10

a = 2±√944/10

a =  2±30.72/10

a = 2-30.72/10 and 2+30.72/10

a = -28.72/10 and 32.72/10

a = -2.872 and 3.272

Frazer is training for a marathon. Last week he ran a total of 19.5 miles. This week he ran a total of 24.3 miles. What is the percentage increase in distance?

Answers

Answer:

19.75%

Step-by-step explanation:

Last month, a boat dealership sold 60 boats. This month, 90 boats were sold. Find the percent increase in sales.

Answers

Answer:

50%

Step-by-step explanation:

90-60 = 30

30÷60 = .5

Find the missing angle.

Answers

Answer is 45°, this is because A right angle triangle has 3 angles. 90°,45°,45°

Lacey picks blueberries and raspberries from her garden. She has ⅕ as many pounds of blueberries as raspberries. If she picks 1⅘ pounds more blueberries, she will have equal weights of berries. Let x represent the weight of raspberries. Write an equation that can be used to find the weight of blueberries Lacey has?

Answers

Answer:

2 1/4 pounds of blueberries

Step-by-step explanation:

Blueberries - b, raspberries - x

Equations as per question:

b = x * 1/5b + 1 4/5 = x

Eliminate b and solve for x:

1/5x = x - 1 4/5x - 1/5x = 1 4/54/5x = 9/5x = 9/5 : 4/5x = 9/5 *5/4x = 9/4 x = 2 1/4

Answer:

2 1/4 pounds of blueberries

Step-by-step explanation:

There are 3 squares and 6 triangles. What is the simplest ratio of squares to total shapes?

Answers

Answer:

6

Step-by-step explanation:

yOU HAVE TO ADD ALL AND DIVIDE

The simplest ratio of squares to total shapes is 1 : 3

What is Ratio?

The ratio is defined as a relationship between two quantities, it is expressed as one divided by the other.

What is a square?

A square is defined as a polygon that has four sides and is a closed, two-dimensional (2D) object. A square has equal and parallel sides on all four sides.

The area of a square is equal to the squared of sides or the multiplication of two sides.

Given that there are 3 squares and 6 triangles.

To determine the simplest ratio of squares to total shapes

The number of squares = 3

The number of triangles = 6

The number of total shapes = 3 + 6 = 9

So, the simplest ratio of squares to total shapes = 3/9

The simplest ratio of squares to total shapes = 1/3

Hence, the simplest ratio of squares to total shapes is 1 : 3

Learn more about Ratio here:

brainly.com/question/1504221

#SPJ2

write the word sentence as an equation. a number y decreased by 9 is 8.
an equation that represents this sentence is ?

it’s not 8

Answers

Answer: Y - 9 = 8

Y = 17

17 - 9 = 8

Step-by-step explanation:

solve ASAP I will Mark brainliest​

Answers

Answer:

u=5/6

Step-by-step explanation:

Answer:

u = 5/6

Step-by-step explanation:

u - 1/12 = 3/4        

  +1/12   +1/12

u=5/6

in order to get 5/6 :

3/4 + 1/12

must get common denominator

3*3/4*3  + 1/12

9/12 + 1/12

10/12

simplify by dividing by 2

5/6

f(x)=(x+1)(x+3)(x-4) in standard form

Answers

Answer:

f(x) = [tex]x^{3}-13x-12[/tex]

Step-by-step explanation:

How many terms are in the expression: 6(3w-2) - (4w + 3) + 12 *

Answers

Answer:

3

Step-by-step explanation:

you'd have w^2, w, and your constant

One side of a rectangle is 3 inches shorter than the other side, and the perimeter is 54 inches. What are the dimensions of the rectangle?

Answers

Answer:

36 inches

Step-by-step explanation:

h(n)=n^2-1; find h(4)

Answers

Answer:

h(4)=4²-1

=16-1

=15

hope it helps.

Answer:

h(4) = 7

Step-by-step explanation:

given ,

h(n) = n^2 ‐ 1

if, h(4) = 4^2 ‐ 1

or, h(4) = 16‐1

or, h(4) = 15

Interest: $160.67
Principal: $2000
Rate:
%
Time: 8 months

Answers

Answer:

12.05%

Step-by-step explanation:

First, converting R percent to r a decimal

r = R/100 = 12.050249999994%/100 = 0.12050249999994 per year,

then, solving our equation

I = 2000 × 0.12050249999994 × 0.666666666667 = 160.67

I = $ 160.67

The simple interest accumulated

on a principal of $ 2,000.00

at a rate of 12.050249999994% per year

for 0.666666666667 years is $ 160.67.

The sum of two numbers is 34. Half of the first number plus one third of the second number is 14. What are the two numbers?

Answers

First number 16, second number 18

PLEASE HELP I HAVE BEEN TRYING TO FIGURE THIS OUT FOR 4 HOURS AND 15 MINUTES

Answers

Answer:

1. C) 3

2. D) -1

3. D) 7^2 - 8*2 - 16

4. B) 75

5. B) 6^2 + (2 - 8)*sqrt(81)

Step-by-step explanation:

1. (10 - (6-4)^2)/2

= (10 - 2^2)/2

= (10 - 4)/2

= 6/2

= 3

2. PEMDAS states that Multiplication is before Subtraction

8 - (5^2-7)/2

= 8 - (25-7)/2

= 8 - 18/2

= 8 - 9

= -1

3. D) 7^2 - (8*2) - 16

= 49 - 16 - 16

= 49 - 32

= 17

4. 3(2 + 3)^2

= 3(5)^2

= 3(25)

= 75

5. 6^2 + (2 - 8)*sqrt(81)

= 36 + (-6*9)

= 36 - 54

= -18

a. find y using the ratio of the sides 6 cm and 8 cm. y/24=6/8
b. find y using the ratios of the sides 15 cm and 20cm.

Answers

Answer:

hi

Step-by-step explanation:

i like oreos

School A has 12 footballs for football practice. School B has 36 footballs for football practice. What is the ratio

Answers

Answer:

1:3

Step-by-step explanation:

12/36=1/3

Answer:

1:3

Step-by-step explanation:

Someone pls help if your good at math I’ll mark brainliest

Answers

Answer:

B

Step-by-step explanation:

9^2 + 12^2 = 225

15^2 = 225

Since we know we are looking for a right triangle, we know the answer cannot be A or D.  Although C also has the correct numbers, you could not draw the right angle anywhere in the triangle.  It must be between the two smaller sides.

The answer is B for the question yes sir

help need plzzzzzzzzz​

Answers

Answer:

The answer to the question provided is possibly 2.

Step-by-step explanation:

[tex] \: \: \: \: \: \: \: \: \: \: \: \: 3y + 77 = 2y + 79 \\ \frac{ - 2y \: \: \: \: \: \: = - 2y}{1y + 77 = 79} \\ \frac{ \: \: \: \: \: \: \: \: - 77 = - 77}{ \frac{1y}{1} = \frac{2}{1} } \\ \\ y = 2[/tex]

Zx and Zy are supplemmentary angles. Zy measures 156 degree
what is the measure of Zx?

Answers

Answer:

Zx = 24 degrees.

Step-by-step explanation:

Supplementary angles are two angles that add up to 180 degrees. If Zy + Zx = 180, and Zy = 156, we can plug in that value and do 156 + Zx = 180, and if you solve that out you can 24.

Let me know if you have any questions

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