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3 years ago

Joe is holding a book over his head. Is he preforming work? why?

1 answer:

3 0

<span>If a book is there on the table, no work is done as no distance is covered. If I hold up a book in my hand and my arm is stretched, if no work is being done, where is my energy going?</span>

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What is the speed of a car that traveled 300 miles in 6 hours?

Misha Larkins [42]

Answer:

Explanation:

300 divided by 6

7 0

3 years ago

Corey runs a 100-meter race. 7 seconds after the race started Corey is 45 meters from the starting line and reaches his max spee

RUDIKE [14]

Answer:

Corey's max speed is $7 \frac{m}{s}$
the distance Corey's covers in z seconds is $7 \frac{m}{s} * z \ s$
$d (z) = 45 m + 7 \frac{m}{s} * z$
$d (x) = 45 m + 7 \frac{m}{s} * (x-7 s)$

Explanation:

<h3>Corey's max speed</h3>

For constant speed, we know:

$v=\frac{distance}{time}$

The distance between the 80 meters and the 45 meters is:

$distance = 80 m - 45 m = 35 m$

and the time it took to reach the 80 meter will be:

$time = 12 s - 7 s = 5 s$

So, Corey's max speed is

$v_{max}=\frac{35 m}{5 s} = 7 \frac{m}{s}$

<h3>How far runs Corey</h3>

As the velocity of Corey's is $v_{max}$ , the distance Corey's covers in z seconds is

$distance = v_{max} * z \ s$

$distance = 7 \frac{m}{s} * z \ s$

<h3>What is Corey's distance from the starting line</h3>

At time 7 + z seconds the distance will be the 45 meters he covers in the first part of the race plus the distance he traveled at constant speed. this is:

$d (z) = 45 m + v_{max} * z$

$d (z) = 45 m +7 \frac{m}{s} * z$

At time x ( x greater or equal to 7 seconds) the distance will be the 45 meters he covers in the first part of the race plus the distance he traveled at constant speed. this is:

$d (x) = 45 m + v_{max} * (x-7 s)$

$d (x) = 45 m + 7 \frac{m}{s} * (x-7 s)$

4 0

2 years ago

A large piece of jewelry has a mass of 132.6 g. a graduated cylinder initially contains 48.6 ml water. when the jewelry is subme

Lerok [7]

The density of the substance is<u> 10.5 g/cm³.</u>

The jewelry is made out of <u>Silver.</u>

Density ρ is defined as the ratio of mass <em>m</em> of the substance to its volume V<em>. </em> The cylinder contains a volume <em>V₁ of water</em> and when the jewelry is immersed in it, the total volume of water and the jewelry is found to be V₂.

The volume <em>V</em> of the jewelry is given by,

$V=V_2 -V_1$

Substitute 48.6 ml for <em>V₁ </em>and 61.2 ml for V₂.

$V=V_2 -V_1\\ =61.2 ml -48.6 ml\\ =12.6 ml$

calculate the density ρ of the jewelry using the expression,

$\rho =\frac{m}{V}$

Substitute 132.6 g for <em>m</em> and 12.6 ml for <em>V</em>.

$\rho =\frac{m}{V}\\ =\frac{132.6 g}{12.6 ml} \\ =10.5 g/ml$

Since $1 ml=1 cm^3$ ,

The density of the jewelry is <u> 10.5 g/cm³.</u>

From standard tables, it can be seen that the substance used to make the jewelry is <u>silver</u><em><u>, </u></em>which has a density 10.5 g/cm³.

4 0

3 years ago

What color will a yellow banana appear when illuminated by yellow light

Phantasy [73]

Answer:

A yellow banana reflects only yellow light,

Explanation:

3 0

2 years ago

What is the magnitude of the gravitational force the apple exerts on earth?

blagie [28]

It's downward vector from the centre of apple in the direction to the centre of the Earth.

4 0

3 years ago