plzzzzzz help.i want answers of these 2 questions.?

Question

a clock has a 20cm long hour arm .wat is the linear speed of its tip?


if y = 1+ 4x + 6*square of x + 4*cube of x + x raised to 4. then the dimensions of y are.

the options for the first 1 are
97 nm/s
30 ultra micron /sec
60 ultramicron/sec
21mm/s

the dimension shud b in the form of LMT

Answer 1

oh ****.... good luck with that lol

Answer 2

There are no "Z"s in the word "please".

The hour arm of a clock rotates, by definition, once every hour. The circumference of the circle is
C = 2*π*R
C = 2*π*(20 cm)
C = 125.66 cm
The linear velocity is the distance divided by the time:
V = C / t
V = (125.66 cm) / (1 hour)
V = (125.66 cm) / (3600 s)
V = 0.00034906 m/s
V = 0.34906 millimeters per second

Both x and y must be dimensionless variables, or else the equation does not pass a basic dimensional check. If x had a dimension such as meters, then the equation would be adding terms with different units, and would therefore be garbage.

Answer 3

As hr arm takes 12 hrs to complete one revolution that means (3600*12)= 43200 sec to rotate through 360 degrees or (2 pi) rad so
Angular velocity ( w) = 2*3.14/43200 ( Angular displacement / time)
w = 6.28/43200 rad / sec
Linear velocity v = r * w ( where r is radius and = 20 cm or 200 mm)
v = (6.28/43200)*200 = .02907 mm/sec or 30 micron/sec appx

Also you can find as below

cicummference = 2*3.14*200 = 1256 mm
time = 12*3600 sec
Velocity = 1256/(12*3600) .02907 mm/sec or 30 micron/sec

Answer 4

tHE CIRCUMFERENCE IS 2*pi*r
=2*3.14*0.2
=1.256 m
now linear velocity
=dist/time
=1.256/24 hours
=1.256/24*60*60
=1.453*10^-5 m/s

And i think both x & y Are dimensionless
bcoz if x & y had dimensions then they could not be added to 1 which is dimensionless in equation

Answer 5

with the data provided the dimension is 1

Answer 6

360 degrees per hour?