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nexus9112 [7]
3 years ago
6

Determine the average acceleration for x(t)=19t^2+7t^3 for a time interval between 3 and 9 seconds

Physics
1 answer:
AleksandrR [38]3 years ago
7 0

Answer:

290

Explanation:

Average acceleration is the change in velocity over change in time.

First, find the velocity by taking the derivative of position.

v(t) = dx/dt

v(t) = 38t + 21t²

At t = 3 and t = 9:

v(3) = 303

v(9) = 2043

So the average acceleration is:

a = Δv / Δt

a = (2043 − 303) / (9 − 3)

a = 290

Use appropriate units.

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Find the vector representing the area of the rectangle with vertices and oriented so that it faces downward. The magnitude of th
sergejj [24]

Answer:

The answer is  "-72 k".

Explanation:

Please find the complete question in the attached file.

Given point:

A=(0,0,0)\\B=(0,8,0)\\C=(9,8,0)\\D=(9,0,0)

\bar{AB} = (0i+8j+0k)-(0i+0j+0k)= 8j\\\\\bar{AC} = (9i+8j+0k)-(0i+0j+0k)= 9i+8j\\\\

Calculating the area:

Area=\left|\begin{array}{ccc}i&j&k\\0&8&0\\9&8&0\end{array}\right|

       =i[8(0)-8(0)]-j[(0-0)]+k[(0-9(8))]\\\\=i[0-0]-j[(0)]+k[(0-72)]\\\\=i[0]-j[(0)]+k[(-72)]\\\\=-72 \ k

3 0
3 years ago
A stone is thrown from the top of a building with an initial velocity of 20 m/s downward. The top of the building is 60 m above
erastova [34]

Answer:

t = 2 s

Explanation:

In order to find the time taken by the stone to fall from the top of the building to the ground we can use 2nd equation of motion. 2nd equation of motion is as follows:

s = Vit + (0.5)gt²

where,

t = time = ?

Vi = Initial Velocity = 20 m/s

s = height of building = 60 m

g = 9.8 m/s²

Therefore,

60 m = (20 m/s)t + (0.5)(9.8 m/s²)t²

4.9t² + 20t - 60 = 0

solving this quadratic equation we get:

t = -6.1 s   (OR)   t = 2 s

Since, the time cannot be negative in magnitude.

Therefore,

<u>t = 2 s</u>

6 0
3 years ago
A bike travels at a constant speed of 3.1 m/s for 6 s. how far does it go?
IgorC [24]
Ah for this problem you are thinking quite a bit hard on. The problem is actually simpler than it looks. The problem states that a bike travels at a constant speed of 3.1 m/s for 6 s and asks how far will it go?. To figure this out you simply need to take 3.1 times 6 s because every second the bike travels 3.1 m. So the answer to this problem would be 18.6 m
8 0
4 years ago
Density of solids What is your hypothesis (or hypotheses) for this experiment?.
valentina_108 [34]

I formulate a hypothesis based on their observations about what occurs when both the rock and the wood are submerged in water.

<h3 /><h3>What is density?</h3>

Density is defined as the mass per unit volume. It is an important parameter in order to understand the fluid and its properties. Its unit is kg/m³.

The mass and density relation is given as

mass = density × volume

I study if the volume or density of items determines whether solid objects float or sink in water in this scientific inquiry I did the experiment of density, mass, and volume using a rock and a standard-shaped piece of wood.

It is critical that the chosen piece of wood is larger than the rock and that the rock be tiny enough to fit inside the measuring cylinder. I see both the rock and a chunk of wood.

Hence I formulate a hypothesis based on their observations about what occurs when both the rock and the wood are submerged in water.

To learn more about the density refers to the link;

brainly.com/question/952755

7 0
3 years ago
Give the molecular explanation of of surface tension
NeX [460]

Explanation:

The surface tension of a liquid results from an imbalance of intermolecular attractive forces, the cohesive forces between molecules: A molecule in the bulk liquid experiences cohesive forces with other molecules in all directions. A molecule at the surface of a liquid experiences only net inward cohesive forces.

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2 years ago
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