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3 years ago

Earth's inner core is:a dense ball of solid metal

1 answer:

7 0

What is one effect of steroid abuse in professional sports?
AThey cause athletes to stop training hard incorrect answer
BThey allow some competitors to gain an unfair advantage incorrect answer
CThey cause athletes to stop competing to win incorrect answer
DThey cause athletes to become selfish

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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

IF you are in Space and push a bowling what happens to you and the bowling ball?

Anastaziya [24]

Answer:

The bowling ball did not change size or shape- the only thing that changed was the amount of gravity that pulls on it. But the mass of the bowling ball would never change. A bowling ball with a mass of 12 pounds on earth will have the mass of 12 pounds on the moon! Mass is the amount of atoms that a space fills.

Explanation:

I hope this helps! :D

4 0

3 years ago

Lila is a track and field athlete.She has to complete four laps around the track, which is 400 meters. The race took her 6 minut

hoa [83]

V=d/t
V=?
d=400m(4)
=1600m
t=6 min.
=360 s

V=1600m/360s
V=4.4m/s

3 0

3 years ago

Wrench is to Hammer as

Elanso [62]

Answer:

Pencil is to pen

Step by step explanation:

They are similar items, as they are both tools, but are different as to how they function.

5 0

3 years ago

Evidence supports the idea that increases in carbon dioxide and methane in Earth's atmosphere are major contributors to global w

PolarNik [594]

Answer: 4. Infrared radiation

Explanation: Both carbon dioxide and methane are excellent absorbers of heat. The heat energy causes the molecule of carbon dioxide and methane to vibrate. As a result of this, the molecules gives up the extra energy by emitting infrared photon.

Therefore, the Evidence that supports the idea that increases in carbon dioxide and methane in Earth's atmosphere are major contributors to global warming is primarily based on the fact that carbon dioxide and methane are excellent absorbers of infrared radiation

5 0

3 years ago