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A metal ball has a mass of 2kg and a volume of 6 m3. What is its density

Lena [83]

Answer: The answer is 333.3333 repeating

Explanation:

Divide the mass by the volume.

8 0

3 years ago

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A baseball player hits a homerun, and the ball lands in the left field seats, which is 103m away from the point at which the bal

Sati [7]

(a) The ball has a final velocity vector

$\mathbf v_f=v_{x,f}\,\mathbf i+v_{y,f}\,\mathbf j$

with horizontal and vertical components, respectively,

$v_{x,f}=\left(20.5\dfrac{\rm m}{\rm s}\right)\cos(-38^\circ)\approx16.2\dfrac{\rm m}{\rm s}$

$v_{y,f}=\left(20.5\dfrac{\rm m}{\rm s}\right)\sin(-38^\circ)\approx-12.6\dfrac{\rm m}{\rm s}$

The horizontal component of the ball's velocity is constant throughout its trajectory, so $v_{x,i}=v_{x,f}$ , and the horizontal distance x that it covers after time t is

$x=v_{x,i}t=v_{x,f}t$

It lands 103 m away from where it's hit, so we can determine the time it it spends in the air:

$103\,\mathrm m=\left(16.2\dfrac{\rm m}{\rm s}\right)t\implies t\approx6.38\,\mathrm s$

The vertical component of the ball's velocity at time t is

$v_{y,f}=v_{y,i}-gt$

where g = 9.80 m/s² is the magnitude of the acceleration due to gravity. Solve for the vertical component of the initial velocity:

$-12.6\dfrac{\rm m}{\rm s}=v_{y,i}-\left(9.80\dfrac{\rm m}{\mathrm s^2}\right)(6.38\,\mathrm s)\implies v_{y,i}\approx49.9\dfrac{\rm m}{\rm s}$

So, the initial velocity vector is

$\mathbf v_i=v_{x,i}\,\mathbf i+v_{y,i}\,\mathbf j=\left(16.2\dfrac{\rm m}{\rm s}\right)\,\mathbf i+\left(49.9\dfrac{\rm m}{\rm s}\right)\,\mathbf j$

which carries an initial speed of

$\|\mathbf v_i\|=\sqrt{{v_{x,i}}^2+{v_{y,i}}^2}\approx\boxed{52.4\dfrac{\rm m}{\rm s}}$

and direction θ such that

$\tan\theta=\dfrac{v_{y,i}}{v_{x,i}}\implies\theta\approx\boxed{72.0^\circ}$

(b) I assume you're supposed to find the height of the ball when it lands in the seats. The ball's height y at time t is

$y=v_{y,i}t-\dfrac12gt^2$

so that when it lands in the seats at t ≈ 6.38 s, it has a height of

$y=\left(49.9\dfrac{\rm m}{\rm s}\right)(6.38\,\mathrm s)-\dfrac12\left(9.80\dfrac{\rm m}{\mathrm s^2}\right)(6.38\,\mathrm s)^2\approx\boxed{119\,\mathrm m}$

6 0

4 years ago

Is NaCH an element? Why or why not?

amm1812

NaCH is not an element, it is a compound. An element can be found and identified on the periodic table to elements. A compound is a combination of two of more elements. NaCH is composed of three elements: Na (sodium), C (carbon) and H (hydrogen), making it a compound.

3 0

3 years ago

Despite the use of diffrent types of measurement in our country

stealth61 [152]

Answer: For standardization purposes

Explanation:

As the question mentions, there were different types of measurements in the country for the same things so measuring a thing in one type of measurement and then comparing it to another was quite cumbersome.

It also made comparing units with the rest of the world difficult. To combat this the SI system was introduced. It gave an international standard for measuring different things based on the metric system. This allowed for worldwide standardization and comparison as things could now be measured in the same units.

6 0

3 years ago

A 1kg skateboard sits at the top of a ramp 20 fr off the ground . How much potential energy does it have ?

Finger [1]

Answer:

196J

Explanation:

Given parameters:

Mass of skateboard = 1kg

Height off the ground = 20m

Unknown:

Potential energy = ?

Solution:

The potential energy is the energy due to the position of a body above the ground.

It is mathematically expressed as:

Potential energy = mass x acceleration due gravity x height

Potential energy = 1 x 9.8 x 20 = 196J

8 0

3 years ago