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mrs_skeptik [129]
1 year ago
7

Determine the value of n so that the vectors A and B are perpendicular: Ā = î + 5j + nk and B = 2î - j + k

Physics
1 answer:
Tanya [424]1 year ago
6 0

If \vec A and \vec B are perpendicular, then their dot product is zero. This means

\vec A \cdot \vec B = (\vec\imath + 5\,\vec\jmath + n\,\vec k) \cdot (2\,\vec\imath - \vec\jmath + \vec k) = 2 - 5 + n = 0

Solving for n is trivial; it follows that n = 3.

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You place a 55.0 kg box on a track that makes an angle of 28.0 degrees with the horizontal. The coefficient of static friction b
Radda [10]

Answer:

\theta=34 \textdegree

Explanation:

From the question we are told that:

Mass m=55kg

Angle \theta =28.0

Coefficient of static friction \alpha =0.680

Generally, the equation for Newtons second Law is mathematically given by

For

\sum_y=0

N=mgcos \theta

for

\sum_x=0

F_{s}=mgsin\theta

Where

F_{s}=\alpha*N\\\\F_{s}=\alpha*m*gcos \theta

F_{s}=0.68*55*9.8*cos 28

F_{s}=323.62N

Therefore

\alpha mgcos \theta=mg sin \theta

\theta=tan^{-1}(0.68)

\theta=34 \textdegree

6 0
2 years ago
Which organelle is the powerhouse of the cell, the site of cellular respiration? A) 2 - nucleus B) 5 - endoplasmic reticulum C)
Paladinen [302]
D) 9- mitochondria
Hope this helps :D
7 0
3 years ago
Help with the two questions above? Correct answers?
LenKa [72]

(6) first choice: the frequency appears higher and wavelength is shorter.

The car approaches a stationary observer and so the sound will appear to have shorter wavelength. This creates an effect of its siren to sound with higher frequency than it would do if both were stationary.

(7) The Doppler formula for frequency in the case of a stationary observer and source approaching it is as follows:

f_O = \frac{v}{v-v_s}\cdot f= \frac{343\frac{m}{s}}{(343-25)\frac{m}{s}}\cdot 400Hz \approx 431Hz

The wavelength is then

\lambda = \frac{343\frac{m}{s}}{431Hz}\approx 0.80 m

The third choice "0.80m; 431Hz" is correct

7 0
2 years ago
If the strength of gravity is 9.8 newtons per kilogram, that means:
Igoryamba
Here, E<span>ach kilogram of mass weighs 9.8 newtons as it's unit value of it.

In short, Your Answer would be Option D

Hope this helps!</span>
4 0
3 years ago
Read 2 more answers
What is sediment and debris, and what role does it play in the way sedimentary rock forms?
quester [9]
Sediments are pieces of rock that come from other rocks that were eroded or broken by wind, water or other mechanical forces. Debris are pieces of other materials that were also swept away. 

When these sediments and debris settle, they create layers. These layers are called beds. In time, several layers of other sediments and debris form on top of each other which press down onto the previous layers. Because of the pressure from the weight of the newer layers, the sediments and debris are pressed together and go through cementation. These then produce sedimentary rocks. 

Metamorphic rocks form when rocks undergo heat and pressure. The heat comes from the friction resulting from the pressure. The heat can also come from radioactive decay. The rocks then slowly bake into new rocks called metamorphic rocks. 

Igneous rocks form when magma and lava cool down. Magma is molten fluid found beneath the surface of the Earth. Lava is magma that has reached the surface of the Earth. When they cool down, they crystallize which make igneous rocks. 

The difference between intrusive and extrusive igneous rocks is that one is made beneath the Earth and the other is made on the surface of the Earth. When magma cools, it takes a long time and the product of this cooling are intrusive igneous rocks. On the other hand, extrusive igneous rock is the result of lava cooling, which does not take as long to cool down because it occurs on the surface of the Earth.

Examples of the following types of rocks:

Sedimentary: limestone, sandstone, siltstone
Metamorphic: Marble, gneiss, slate
Igneous: Gabbro (intrusive), granite (Intrusive), obsidian (extrusive)

 


6 0
3 years ago
Read 2 more answers
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