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2 years ago

In physics, what is the positive and negative sign used for when applied to velocity and acceleration?

Physics

1 answer:

Kobotan [32]2 years ago

6 0

Answer:

Opposite direction

Explanation:

For example: The first object travels in the direction pointing to east, while the other one travels pointing to the west.

The first object will have a positive value while the second one will have a negative, cause it's going to the opposite direction

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Suppose that you'd like to find out if a distant star is moving relative to the earth. The star is much too far away to detect a

rjkz [21]

Answer:

The speed will be "18km/s". A further explanation is given below.

Explanation:

According to the question, the values are:

Wavelength,

$\lambda = 656.46 \ nm$

$\Delta \lambda = 0.04$

$c=3\times 10^8$

As we know,

⇒ $\frac{\Delta \lambda}{\lambda} =\frac{v}{c}$

On substituting the values, we get

⇒ $\frac{656.46}{0.04} =\frac{v}{3\times 10^8}$

⇒ $v=\frac{656.46}{0.04} (3\times 10^8)$

⇒ $=16411.5\times 3\times 10^8$

⇒ $=18280 \ m/s$

or,

⇒ $=18 \ km/s$

8 0

2 years ago

Air enters a nozzle steadily at 2.21 kg/m3 and 20 m/s and leaves at 0.762 kg/m3 and 150 m/s. If the inlet area of the nozzle is

saveliy_v [14]

Answer:

a) The mass flow rate through the nozzle is 0.27 kg/s.

b) The exit area of the nozzle is 23.6 cm².

Explanation:

a) The mass flow rate through the nozzle can be calculated with the following equation:

$\dot{m_{i}} = \rho_{i} v_{i}A_{i}$

Where:

$v_{i}$ : is the initial velocity = 20 m/s

$A_{i}$ : is the inlet area of the nozzle = 60 cm²

$\rho_{i}$ : is the density of entrance = 2.21 kg/m³

$\dot{m} = \rho_{i} v_{i}A_{i} = 2.21 \frac{kg}{m^{3}}*20 \frac{m}{s}*60 cm^{2}*\frac{1 m^{2}}{(100 cm)^{2}} = 0.27 kg/s$

Hence, the mass flow rate through the nozzle is 0.27 kg/s.

b) The exit area of the nozzle can be found with the Continuity equation:

$\rho_{i} v_{i}A_{i} = \rho_{f} v_{f}A_{f}$

$0.27 kg/s = 0.762 kg/m^{3}*150 m/s*A_{f}$

$A_{f} = \frac{0.27 kg/s}{0.762 kg/m^{3}*150 m/s} = 0.00236 m^{2}*\frac{(100 cm)^{2}}{1 m^{2}} = 23.6 cm^{2}$

Therefore, the exit area of the nozzle is 23.6 cm².

I hope it helps you!

5 0

2 years ago

Read 2 more answers

If the distance d (in meters) traveled by an object in time t (in seconds) is given by the formula d=a+bt2, the si units of a an

ss7ja [257]

Distance , d = a+b $t^2$

The unit of d is in meter and t is in seconds.

So the unit of a a must be meter.

Now we have unit of b $t^2$ is meter.

So unit of b* $second^2$ = meter

Unit of b = meter/ $second^2$

So unit of a = m and unit of b = m/ $s^2$ .

8 0

2 years ago

What is work done in physics and how can it be calculated

shusha [124]

Work is done when a force is applied to an object moves that object. the work is calculated by multiplying the force by the amount of movement of an object

8 0

2 years ago

Read 2 more answers

When light passes through an object unchanged, scientists call that process _____.

Nataly [62]

<u>Answer</u>:

When light passes through an object unchanged, scientists call that process Transmission.

<u>Explanation</u>:

Transmission is the process where all the light that is passed through the material moves via the material without being absorbed. The Transmission depends on the affected radiation.The Transmittance of the medium is defined as the ratio between transmitted radiant power and incident radiant power. The light that is passed through the medium and not reflected will be either scattered or reflected. The light can be transmitted only through transparent or translucent material. Opaque object does not allows transmission of light.

5 0

3 years ago