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3 years ago

Looking at the periodic table which element would you think is the best conductor of electricity?

Physics

1 answer:

Contact [7]3 years ago

7 0

Answer:

Zinc

Explanation:

Zinc is a transition metal

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What word is modified by an adjectival phrase in the following sentence? The savings to the project manager at NASA were substan

DedPeter [7]

I am pretty sure that the<span> word which is modified by an adjectival phrase in the following sentence is </span>being revealed by the second options from the box represented above : b. project. I choose this one as a correct answer because it is clear that this word is <span>modified by the phrase :"to the project manager". Hope it will help!</span>

8 0

3 years ago

The height of a typical playground slide is about 1.8 m and it rises at an angle of 30 ∘ above the horizontal.

Salsk061 [2.6K]

Answer:

$5.94\ \text{m/s}$

$1.7$

$0.577$

Explanation:

g = Acceleration due to gravity = $9.81\ \text{m/s}^2$

$\theta$ = Angle of slope = $30^{\circ}$

v = Velocity of child at the bottom of the slide

$\mu_k$ = Coefficient of kinetic friction

$\mu_s$ = Coefficient of static friction

h = Height of slope = 1.8 m

The energy balance of the system is given by

$mgh=\dfrac{1}{2}mv^2\\\Rightarrow v=\sqrt{2gh}\\\Rightarrow v=\sqrt{2\times 9.81\times 1.8}\\\Rightarrow v=5.94\ \text{m/s}$

The speed of the child at the bottom of the slide is $5.94\ \text{m/s}$

Length of the slide is given by

$l=h\sin\theta\\\Rightarrow l=1.8\sin30^{\circ}\\\Rightarrow l=0.9\ \text{m}$

$v=\dfrac{1}{2}\times5.94\\\Rightarrow v=2.97\ \text{m/s}$

The force energy balance of the system is given by

$mgh=\dfrac{1}{2}mv^2+\mu_kmg\cos\theta l\\\Rightarrow \mu_k=\dfrac{gh-\dfrac{1}{2}v^2}{gl\cos\theta}\\\Rightarrow \mu_k=\dfrac{9.81\times 1.8-\dfrac{1}{2}\times 2.97^2}{9.81\times 0.9\cos30^{\circ}}\\\Rightarrow \mu_k=1.73$

The coefficient of kinetic friction is $1.7$ .

For static friction

$\mu_s\geq\tan30^{\circ}\\\Rightarrow \mu_s\geq0.577$

So, the minimum possible value for the coefficient of static friction is $0.577$ .

8 0

3 years ago

a worker in a factory has discovered a material that is very confusing.it can be stored in a container but it can also flow from

tamaranim1 [39]

Answer:

liquid?

Explanation:

liquid: A substance that flows and keeps no definite shape because its molecules are loosely packed and constantly moving. It takes the shape of its container but maintains constant volume.

7 0

2 years ago

When a skydiver jumps out of a plane in free fall, they hit a

IRISSAK [1]

Answer:

By decreasing the surface area exposed to the air. Vertical body position instead of horizontal.

Explanation:

So the terminal velocity formula is as follows.

v = sqrt[(2*m*g)/(p*A*c)]

m = mass

g = 9.81 m/s^2

p = density of air

A = surface area of object

c = Drag coefficient

So the only thing you can change in mid-air is surface area.

5 0

3 years ago

A 20.0 kg suitcase is raised 3.0 m above a platform. How much work is done on the suitcase?

Lisa [10]

Answer:

600

Explanation:

m=20

g=10m\s2

h=3m

we have

w=m*g*h

=20*10*3

=600joule

3 0

4 years ago