The chemical symbol for the element zinc is Zn.
<h3>What is element?</h3>
A chemical element is the one which reacts with other elements to form a compound.
Any chemical symbol must have its first letter written in Uppercase. If the element has two letter chemical symbol, then it should be written in lowercase.
Thus, the student wrote Zn as the chemical symbol of Zinc on the whiteboard.
Learn more about element.
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The body will take 20 seconds to cover a distance of 1000 m i.e. 1 km
Answer:
a)
, b)
,
, 
Explanation:
a) The system mass-spring is well described by the following equation of equilibrium:

After some handling in physical and mathematical definition, the following non-homogeneous second-order linear differential equation:
The solution of this equation is:

The velocity function is:

Initial conditions are:

Equations at
are:

The spring constant is:


After some algebraic handling, amplitude and phase angle are found:


The position can be described by this function:

b) The period of the motion is:


The amplitude is:

The phase of the motion is:

Answer:
Choices A, B, and C are correct.
Explanation:
Let us look at each of the choices one by one:
A. It is a vector
Yes. Velocity is a vector, or it's a speed with direction.
B. It is the change in displacement divided by the change in time.
Yes. The velocity can be written as

where
is the displacement—a vector quantity.
C. It can be measured in meters per second.
Yes. The units of velocity are m/s, but also with a unit vector indicating the direction.
D. It is the slope of the acceleration vs. time graph.
Nope. The velocity is the slope of displacement vs. time graph.
Hence, only choices A, B, and C are correct.
Explanation:
The power P dissipated by a heater is defined as

where V is the voltage and I is the current.
a) The current running through a 130-W heater is

b) The resistance <em>R</em><em> </em>of the heater is

where
is our familiar Ohm's Law.

