(a) Differentiate the position vector to get the velocity vector:
<em>r</em><em>(t)</em> = (3.00 m/s) <em>t</em> <em>i</em> - (4.00 m/s²) <em>t</em>² <em>j</em> + (2.00 m) <em>k</em>
<em>v</em><em>(t)</em> = d<em>r</em>/d<em>t</em> = (3.00 m/s) <em>i</em> - (8.00 m/s²) <em>t</em> <em>j</em>
<em></em>
(b) The velocity at <em>t</em> = 2.00 s is
<em>v</em> (2.00 s) = (3.00 m/s) <em>i</em> - (16.0 m/s) <em>j</em>
<em></em>
(c) Compute the electron's position at <em>t</em> = 2.00 s:
<em>r</em> (2.00 s) = (6.00 m) <em>i</em> - (16.0 m) <em>j</em> + (2.00 m) <em>k</em>
The electron's distance from the origin at <em>t</em> = 2.00 is the magnitude of this vector:
||<em>r</em> (2.00 s)|| = √((6.00 m)² + (-16.0 m)² + (2.00 m)²) = 2 √74 m ≈ 17.2 m
(d) In the <em>x</em>-<em>y</em> plane, the velocity vector at <em>t</em> = 2.00 s makes an angle <em>θ</em> with the positive <em>x</em>-axis such that
tan(<em>θ</em>) = (-16.0 m/s) / (3.00 m/s) ==> <em>θ</em> ≈ -79.4º
or an angle of about 360º + <em>θ</em> ≈ 281º in the counter-clockwise direction.
Answer:
density of cube =11.605 g/cm³
Explanation:
density of a substance is the mass per unit volume of that substance.
the density of a substance = 
volume of a cube = l³,
l = 19.0mm , lets convert mm to cm
1mm = 0.1cm, thus, 19mm =19*0.1 =1.9cm
length of cube =1.9cm
volume of cube = 1.9³
density of cube = 
density of cube =11.605 g/cm³
The wavenumber and (b) the wavelength of the radiation used by an fm radio transmitter broadcasting at 92. 0 mhz will be 31.25 *
and 0.032 *
m respectively
Forms of electromagnetic radiation like radio waves, light waves or infrared (heat) waves make characteristic patterns as they travel through space. Each wave has a certain shape and length. The distance between peaks (high points) is called wavelength.
Wavenumber, also called wave number, a unit of frequency, often used in atomic, molecular, and nuclear spectroscopy, equal to the true frequency divided by the speed of the wave and thus equal to the number of waves in a unit distance.
wavelength = ?
frequency = 92 m Hz = 92 *
Hz
speed of light = 3 *
m/s
speed of light = frequency * wavelength
wavelength = speed of light / frequency
= 3 *
/ 92 *
= 0.032 *
m
wavenumber = 1 / wavelength
= 1 / 0.032 *
m
= 31.25 *

To learn more about electromagnetic radiation here
brainly.com/question/10759891
#SPJ4
We need more evidence to be provided
Answer:
Explanation:
Let
be the time required to make one revolution.
Let
be the radius of the circular path.
Let
be the distance travelled by ball in one revolution.
As we know,the distance travelled in one revolution is the circumference of the circle.
So,
Given,

Speed of an object moving is circular path is define as the ratio of distance travelled in one revolution to the time taken by the object to complete one revolution.
Let
be the speed of the ball.

So,the speed of the ball is 