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2 years ago

Name nine elements that have been around so long that we don't even know when they

2 answers:

8 0

What was the first known element? Actually, there were nine elements known to ancient man. They were gold, silver, copper, iron, lead, tin, mercury, sulfur, and carbon.

lora16 [44]2 years ago

7 0

Answer:

gold, silver, copper, iron, lead, tin, mercury, sulfur, and carbon

Explanation:

gold, silver, copper, iron, lead, tin, mercury, sulfur, and carbon

- (These are the most longest elements that have been around very long )

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Centripetal is a word used in science to mean

bogdanovich [222]

: the force that is necessary to keep an object moving in a curved path and that is directed inward toward the center of rotation a string on the end of which a stone is whirled about exerts centripetal<span> force on the stone — compare centrifugal force.</span>

7 0

3 years ago

What is the resultant force on the human cannonball in the

Svetllana [295]

Answer:

heart

Explanation:

4 0

2 years ago

What is the average speed of a cheetah that runs 88 m in 5 seconds

vovangra [49]

So, the average speed of the Cheetah is 17.6 m/s.

<h3>Introduction</h3>

Hello ! I'm Deva from Brainly Indonesia. This time, I will help regarding the average speed. The average speed is obtained from finding the average of the speeds that occur or can be detected from the division between distance and travel time. The average speed can be formulated by :

$\boxed{\sf{\bold{\overline{v} = \frac{s}{t}}}}$

With the following condition :

$\sf{\overline{v}}$ = average speed (m/s)
s = shift or distance objects from initial movement (m)
t = interval of the time (s)

<h3>Problem Solving</h3>

We know that :

s = shift = 88 m
t = interval of the time = 5 seconds

What was asked :

$\sf{\overline{v}}$ = average speed = ... m/s

Step by step :

$\sf{\overline{v} = \frac{s}{t}}$

$\sf{\overline{v} = \frac{88}{5}}$

$\boxed{\sf{\overline{v} = 17.6 \: m/s}}$

So, the average speed of the Cheetah is 17.6 m/s.

5 0

2 years ago

as an aid in understanding this problem. The drawing shows a positively charged particle entering a 0.61-T magnetic field. The p

miv72 [106K]

Answer:

E = 420.9 N/C

Explanation:

According to the given condition:

$Net\ Force = 2(Magnetic\ Force)\\Electric\ Force - Magnetic\ Force = 2(Magnetic\ Force)\\Electric\ Force = 3(Magnetic\ Force)\\qE = 3qvBSin\theta\\E = 3vBSin\theta$

where,

E = Magnitude of Electric Field = ?

v = speed of charge = 230 m/s

B = Magnitude of Magnetic Field = 0.61 T

θ = Angle between speed and magnetic field = 90°

Therefore,

$E = (3)(230\ m/s)(0.61\ T)Sin90^o$

3 0

2 years ago

If you drop a rock off a cliff and it hits the ground 3 seconds later how tall is that cliff

skelet666 [1.2K]

Answer:

Basic kinematics, negating drag and assuming ideal conditions, we use the equation:

d=vi*t+1/2*a*t^2

Since vi is 0 (we know this because you’re dropping it, not throwing it)…

…and the only acceleration acting on it is gravity, a=9.8 m/s^2…

…we get

d=1/2(9.8)(5)^2

Explanation:

Some quick mental math tells us that this is about 125 m.

Plugging it in, we find it to be 122.5 m.

6 0

3 years ago