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3 years ago

11

Night vision glasses detect energy given off by objects as (2 points)

1 answer:

Allushta [10]3 years ago

6 0

The answer here would be infrared waves. Hot objects and humans give off heat in the form of infrared light, thermal imaging technology in the goggles enable them to catch this light emitted by these objects

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Mike walks 200 km in 6 hours.he then walks another 100km in 4 hours .what is his average speed?

kolbaska11 [484]

Average speed is defined as the ratio of total distance covered in total given time

$speed = \frac{distance}{time}$

here we know that total distance that man moved is

$d_1 = 200 km$

$d_2 = 100 km$

so total distance is

$d = d_1 + d_2$

$d = 200 km + 100 km$

$d = 300 km$

now here total time of the motion is

$t_1 = 6 hours$

$t_2 = 4 hours$

total time will be given as

$t = t_1 + t_2$

$t = 6 + 4 = 10 hours$

now by above formula

$v_{avg} = \frac{300}{10}$

$v_{avg} = 30 km/h$

so his average speed is 30 km/h

8 0

4 years ago

A protostar is _____.

defon

<u>Answer</u>

5.the stage before a star becomes a main sequence star

<u>Explanation</u>

A protostar is a small star that is still gathering its masses. When it forms enough masses it make a parent molecular cloud.

This been the case, from the choices given, the correct statement about a protostar is;

5.the stage before a star becomes a main sequence star

8 0

3 years ago

Read 2 more answers

Continuous and aligned fiber-reinforced composite with cross-sectional area of 340 mm2 (0.53 in.2) is subjected to a longitudina

Alecsey [184]

(a) 23.4

The fiber-to-matrix load ratio is given by

$\frac{F_f}{F_m}=\frac{E_f V_f}{E_m V_m}$

where

$E_f = 131 GPa$ is the fiber elasticity module

$E_m = 2.4 GPa$ is the matrix elasticity module

$V_f=0.3$ is the fraction of volume of the fiber

$V_m=0.7$ is the fraction of volume of the matrix

Substituting,

$\frac{F_f}{F_m}=\frac{(131 GPa)(0.3)}{(2.4 GPa)(0.7)}=23.4$ (1)

(b) 44,594 N

The longitudinal load is

F = 46500 N

And it is sum of the loads carried by the fiber phase and the matrix phase:

$F=F_f + F_m$ (2)

We can rewrite (1) as

$F_m = \frac{F_f}{23.4}$

And inserting this into (2):

$F=F_f + \frac{F_f}{23.4}$

Solving the equation, we find the actual load carried by the fiber phase:

$F=F_f (1+\frac{1}{23.4})\\F_f = \frac{F}{1+\frac{1}{23.4}}=\frac{46500 N}{1+\frac{1}{23.4}}=44,594 N$

(c) 1,906 N

Since we know that the longitudinal load is the sum of the loads carried by the fiber phase and the matrix phase:

$F=F_f + F_m$ (2)

Using

F = 46500 N

$F_f = 44594 N$

We can immediately find the actual load carried by the matrix phase:

$F_m = F-F_f = 46,500 N - 44,594 N=1,906 N$

(d) 437 MPa

The cross-sectional area of the fiber phase is

$A_f = A V_f$

where

$A=340 mm^2=340\cdot 10^{-6}m^2$ is the total cross-sectional area

Substituting $V_f=0.3$ , we have

$A_f = (340\cdot 10^{-6} m^2)(0.3)=102\cdot 10^{-6} m^2$

And the magnitude of the stress on the fiber phase is

$\sigma_f = \frac{F_f}{A_f}=\frac{44594 N}{102\cdot 10^{-6} m^2}=4.37\cdot 10^8 Pa = 437 MPa$

(e) 8.0 MPa

The cross-sectional area of the matrix phase is

$A_m = A V_m$

where

$A=340 mm^2=340\cdot 10^{-6}m^2$ is the total cross-sectional area

Substituting $V_m=0.7$ , we have

$A_m = (340\cdot 10^{-6} m^2)(0.7)=238\cdot 10^{-6} m^2$

And the magnitude of the stress on the matrix phase is

$\sigma_m = \frac{F_m}{A_m}=\frac{1906 N}{238\cdot 10^{-6} m^2}=8.0\cdot 10^6 Pa = 8.0 MPa$

(f) $3.34\cdot 10^{-3}$

The longitudinal modulus of elasticity is

$E = E_f V_f + E_m V_m = (131 GPa)(0.3)+(2.4 GPa)(0.7)=41.0 Gpa$

While the total stress experienced by the composite is

$\sigma = \frac{F}{A}=\frac{46500 N}{340\cdot 10^{-6}m^2}=1.37\cdot 10^8 Pa = 0.137 GPa$

So, the strain experienced by the composite is

$\epsilon=\frac{\sigma}{E}=\frac{0.137 GPa}{41.0 GPa}=3.34\cdot 10^{-3}$

3 0

3 years ago

In what state of matter are particles vibrating and moving at high speeds?

VARVARA [1.3K]

Answer:

Gas

Explanation:

6 0

3 years ago

What is the net force of a 25 g object with an acceleration of 3 m/s^2? 100PTS

gayaneshka [121]

Explanation:

Force=Mass×acceleration

force=25×3

force=75N

5 0

3 years ago

Read 2 more answers