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denpristay [2]
3 years ago
13

Two vectors are given as A⃗ = 2i^ + 3j^ − 3k^ and B⃗ = -1i^ + 5j^ + 3k^. Find A⃗ ⋅ B⃗

Physics
1 answer:
lesya692 [45]3 years ago
6 0

Answer:

A·B = 4

Explanation:

Given that,

Vector A = 2i+3j-3k

Vector B = -i+5j+3k

We need to find the value of A·B.

We know that,

i·i=j·j=k·k = 1 and i·j=j·k=k·i=0

So,

A\cdot B=(2i+3j-3k)\cdot (-i+5j+3k)\\\\=-2+5(3)+(-3)(3)\\\\=-3+15-9\\\\=4

So, the value of A·B is equal to 4.

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The cunninghams are moving across the country. Mr.cunningham leaves 2.5 hours before mrs.cunningham. If he averages 40 mph and s
Eva8 [605]

When she starts out, he is (40x2.5)= 100 miles ahead of her.

She gains (65-40)= 25 miles on him every hour.

It takes her (100/25)= 4 hours to catch up to him.

5 0
3 years ago
Skater begins to spend with arms held out at shoulder height. The skater wants to match the speed of the spin to the beat of the
Aleksandr [31]

Answer:

the moment of inertia with the arms extended is Io and when the arms are lowered the moment

I₀/I > 1    ⇒   w > w₀

Explanation:

The angular momentum is conserved if the external torques in the system are zero, this is achieved because the friction with the ice is very small,

           L₀ = L_f

           I₀ w₀ = I w

          w =\frac{I_o}{I} w₀

where we see that the angular velocity changes according to the relation of the angular moments, if we approximate the body as a cylinder with two point charges, weight of the arms

          I₀ = I_cylinder + 2 m r²

where r is the distance from the center of mass of the arms to the axis of rotation, the moment of inertia of the cylinder does not change, therefore changing the distance of the arms changes the moment of inertia.

If we say that the moment of inertia with the arms extended is Io and when the arms are lowered the moment will be

        I <I₀

        I₀/I > 1    ⇒   w > w₀

therefore the angular velocity (rotations) must increase

in this way the skater can adjust his spin speed to the musician.

7 0
3 years ago
What happens when the sun emits more energy than normal
xxTIMURxx [149]

Answer:

When the Sun emits more amount of energy than normal, "Solar flares and sunspots" occur, increasing temperature of Earth. Explanation: The Earth's temperature is governed by many factors. One of these factors is 'Solar flare'.

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Alex777 [14]

Answer

200km {h}^{ - 2}

Explanation

Acceleration =  \frac{final \:  \:  \: velocity - initial \:  \: velocity }{time}  \\  =  \frac{(40 - 30)km {h}^{ - 1} }{0.05h}  \\  =  \frac{10}{0.05}  \\  = 200km {h}^{ - 2}

Hope this helps you.

Let me know if you have any other questions :-):-)

6 0
3 years ago
Read 2 more answers
A major feature of the solar system is that as planets get farther away from the sun they, _________ a. Are warmer b. Have fewer
defon
D.
Have a longer revolution time since they definitely do not get warmer, They do not have fewer moons (Jupiter has about 100 and earth has 1) they are not smaller in diameter (Earth v Jupiter)
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