Lithium shares more properties with Sodium, because they have the same number of valence electrons (one). Choice 1 is correct. Hope this helps!
Answer:
The tangential velocity of a rotating object is:
v = r*w
where r is the radius, and w is the angular velocity.
w = 2*pi*f
where f is the frequency.
We know that the record plater does 11 revolutions in 20 seconds, then it does:
11 rev/20s = 0.55 rev/s = f
then we have:
w = 2*pi*0.55 s^-1 = 2*3.14*0.55 s^-1 = 3.454 s^-1
The radius of a record player is really variable, it is around 10 inches, so i will use r = 10in, which is the rotating part of the record player.
then the tangential velocity is:
v = 10in*3.454 s^-1 = 34.54 in/s
This being a perfect collision means no energy is lost during the collision. Because this question asks for speed and not velocity, the speed will be the same because the final energy is the same. The speed after the collision would therefore be 1.27 m/s.
Answer:
Her speed at the bottom of the slope is 25.665 m/s
Explanation:
Here we have
Initial velocity, v₁= 15 m/s
Final velocity = v₂
The energy balance present in the system can be represented as
Where:
m = Mass of the cyclist = 70 kg
W = work done by the drag force = 
Where:
d = Distance traveled = 450 m
Therefore,
and
= 658.714 m²/s²
v₂ = 25.665 m/s
Her speed at the bottom of the slope = 25.665 m/s.
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