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mrs_skeptik [129]
2 years 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]2 years 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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A car travels on a straight, level road. (a) Starting from rest, the car is going 38 ft/s (26 mi/h) at the end of 4.0 s. What is
lbvjy [14]

Answer:

a)9.5\frac{ft}{s^2}\\ b) 12.66\frac{ft}{s^2}

Explanation:

A body has acceleration when there is a change in the velocity vector, either in magnitude or direction. In this case we only have a change in magnitude. The average acceleration represents the speed variation that takes place in a given time interval.

a)

a_{avg}=\frac{\Delta v}{\Delta t}\\a_{avg}=\frac{v_{f}-v_{i}}{t_{f}- t_{i}}\\a_{avg}=\frac{38\frac{ft}{s}-0}{4 s- 0}=9.5\frac{ft}{s^2}\\

b)

a_{avg}=\frac{\Delta v}{\Delta t}\\a_{avg}=\frac{v_{f}-v_{i}}{t_{f}- t_{i}}\\a_{avg}=\frac{76\frac{ft}{s}-38\frac{ft}{s}}{7 s- 4s}\\a_{avg}=\frac{38\frac{ft}{s}}{3s}=12.66\frac{ft}{s^2}

8 0
3 years ago
If you wanted to soundproof your bedroom, the best material to line the walls would be
Vsevolod [243]

Answer:

a soft foam material because soft materials absorb sound better

6 0
3 years ago
What automotive system keeps the vehicle's tires in contact with the road?        A. The steering system   B. The suspension sys
taurus [48]
The answer is D transmission
3 0
3 years ago
Read 2 more answers
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Answer:

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5 0
3 years ago
how much horse power is needed to move a box that has a force of 1,492 newtons a distance of 2 meters in 1 second
stellarik [79]

This one is a piece 'o cake if you know the definition
of a horsepower, and impossible if you don't.

It is:            1 horsepower = 746 watts

Also, remember that  1 watt = 1 joule/second
                
Now:            Work = (force) x (distance)

To move this box 2 meters,

                     Work = (1,492 newtons) x (2 meters) = 2,984 joules

If you accomplished that feat in 1 second,
then you produced power of

                               (2,984 / 1) (joule/second) = 2,984 watts . 

                             (2,984 watt) x (1 HP / 746 watt) = 4 horsepower .

That's the solution, applying bullet-proof math and physics to the
given data.  But in the real world, I guarantee that you didn't do that.
______________________________________

By the way ... a comment regarding the terminology in the question:

The box doesn't "have a force" of 1,492 newtons.  That's the force
with which you ... or a horse, or an ox ... pushed against the box
in order to move it.

(And, if I might observe, that force is about 336 pounds,
so my money would be on the horse or the ox.)
5 0
3 years ago
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