1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
ziro4ka [17]
3 years ago
6

A skydiver jumps from a stationary helicopter and reaches a steady vertical speed. She then opens her parachute. Which statement

about the falling skydiver is correct?
A As her parachute opens, her acceleration is upwards.
B As she falls at a steady speed with her parachute open, her weight is zero.
C When she accelerates, the resultant force on her is zero.
alda
D When she falls at a steady speed, air resistance is zero.
Physics
1 answer:
Bess [88]3 years ago
4 0

Answer:

A) As her parachute opens, her acceleration is upwards.

Explanation:

The acceleration is the rate of change of the velocity.

Thus, if you have positive velocity and positive acceleration, your velocity increases

If you have positive velocity and negative acceleration, then your velocity decreases.

(The opposite happens when you have negative velocity).

Now, when the skydiver is falling, her velocity is downwards.

When she opens her parachute, her velocity downwards decreases.

This means that when she opens her parachute, she will have an acceleration in the opposite direction to her velocity, then at this point her acceleration is upwards.

We can conclude that the correct option is:

A) As her parachute opens, her acceleration is upwards.

You might be interested in
Two people stand across from one another at the top edges of identical buildings, 50 meters above the ground. One person throws
cricket20 [7]

Answer:

C

Explanation:

Hope this helps!!!!

6 0
3 years ago
Consider an optical cavity of length 40 cm. Assume the refractive index is 1, and use the formula for Icavity vs wavelength to p
Bad White [126]

Answer:

Diode Lasers  

Consider a InGaAsP-InP laser diode which has an optical cavity of length 250  

microns. The peak radiation is at 1550 nm and the refractive index of InGaAsP is  

4. The optical gain bandwidth (as measured between half intensity points) will  

normally depend on the pumping current (diode current) but for this problem  

assume that it is 2 nm.  

(a) What is the mode integer m of the peak radiation?  

(b) What is the separation between the modes of the cavity? Please express your  

answer as Δλ.  

(c) How many modes are within the gain band of the laser?  

(d) What is the reflection coefficient and reflectance at the ends of the optical  

cavity (faces of the InGaAsP crystal)?  

(e) The beam divergence full angles are 20° in y-direction and 5° in x-direction  

respectively. Estimate the x and y dimensions of the laser cavity. (Assume the  

beam is a Gaussian beam with the waist located at the output. And the beam  

waist size is approximately the x-y dimensions of the cavity.)  

Solution:  

(a) The wavelength λ of a cavity mode and length L are related by  

n

mL

2

λ = , where m is the mode number, and n is the refractive index.  

So the mode integer of the peak radiation is  

1290

1055.1

10250422

6

6

= ×

××× == −

−

λ

nL

m .  

(b) The mode spacing is given by nL

c f 2

=Δ . As

λ

c f = , λ

λ

Δ−=Δ 2

c f .  

Therefore, we have nm

nL f

c

20.1

)10250(42

)1055.1(

2 || 6

2 2 26

= ×××

× ==Δ=Δ −

− λλ λ .  

(c) Since the optical gain bandwidth is 2nm and the mode spacing is 1.2nm, the  

bandwidth could fit in two possible modes.  

For mode integer of 1290, nm

m

nL 39.1550

1290

10250422 6

= ××× ==

−

λ

Take m = 1291, nm

m

nL 18.1549

1291

10250422 6

= ××× ==

−

λ

Or take m = 1289, nm

m

nL 59.1551

1289

10250422 6

= ××× ==

−

λ .

Explanation:

8 0
3 years ago
The sound source of a ship’s sonar system operates at a frequency of 22.0 kHz . The speed of sound in water (assumed to be at a
Degger [83]

Answer:

147.456077993 Hz

Explanation:

f_0 = Frequency of the sonar = 22 kHz

v_w = Velocity of the whale = 4.95 m/s

v = Speed of sound in water = 1482 m/s

The difference in frequency is given by

\Delta f=f_0\times\dfrac{2v_{w}}{v-v_w}\\\Rightarrow \Delta f=22000\times\dfrac{2\times 4.95}{1482-4.95}\\\Rightarrow \Delta f=147.456077993\ Hz

The difference in frequency is 147.456077993 Hz

6 0
3 years ago
A certain corner of a room is selected as the origin of a rectangular coordinate system. If a fly is crawling on an adjacent wal
Helga [31]

Answer:

2.59 m

Explanation:

Coordinates of origin = (0, 0)

Coordinates of Point p where the fly reach = (2.3 m, 1.2 m)

Use the distance formula of coordinates to find the distance between the origin and the point P.

d=\sqrt{\left ( x_{2}-x_{1} \right )^{2}+\left ( y_{2}-y_{1} \right )^{2}}

d=\sqrt{\left ( 2.3- 0 \right )^{2}+\left ( 1.2-0 \right )^{2}}

d = 2.59 m

Thus, the distance between the origin and the point P is 2.59 m.

5 0
3 years ago
QUESTION 36
mel-nik [20]

Answer:

Explanation:

m = ρV = 1.03( 1000 kg/m³)(π(2² m²)(3.0 m)) = 12360π kg

m ≈ 38,830 kg

5 0
3 years ago
Other questions:
  • Use the drop-down menus to complete the statements.
    14·2 answers
  • (Look at the minerals in the linked picture)
    5·1 answer
  • A pressure that will support a column of Hg to a height of 256 mm would support a column of water to what height? The density of
    7·1 answer
  • A(n)... is a material that takes in a wave when the wave hits it
    8·1 answer
  • Suppose that water is pouring into a swimming pool in the shape of a right circular cylinder at a constant rate of 5 cubic feet
    15·1 answer
  • Explain how it is possible for the smallest white dwarfs to be the most massive.
    11·1 answer
  • I WILL MARK YOU THE BRAINLIEST
    15·2 answers
  • Please help me, anyone????
    12·1 answer
  • An ocean liner leaves New York City and travels 18.0o north of east for 155 km. How far east and how far north has it gone? In o
    14·1 answer
  • if the current through a resistor is increased by a factor of 4, how does this affect the power dissipated?
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!