Solution :
Given
Diameter of the roulette ball = 30 cm
The speed ball spun at the beginning = 150 rpm
The speed of the ball during a period of 5 seconds = 60 rpm
Therefore, change of speed in 5 seconds = 150 - 60
= 90 rpm
Therefore,
90 revolutions in 1 minute
or In 1 minute the ball revolves 90 times
i.e. 1 min = 90 rev
60 sec = 90 rev
1 sec = 90/ 60 rec
5 sec = 
= 75 rev
Therefore, the ball made 75 revolutions during the 5 seconds.
I think the correct answer is C
It's and if, then statement!
Answer:
1. The length is 8.35m
2. The period on the moon is 14.05 secs
Explanation:
1. Data obtained from the question. This includes the following:
Period (T) = 5.8 secs
Acceleration due to gravity (g) = 9.8 m/s2
Length (L) =...?
The length can be obtained by using the formula given below:
T = 2π√(L/g)
5.8 = 2π√(L/9.8)
Take the square of both side
(5.8)^2 = 4π^2 x L/ 9.8
Cross multiply
4π^2 x L = (5.8)^2 x 9.8
Divide both side by 4π^2
L = (5.8)^2 x 9.8 / 4π^2
L= 8.35 m
2. Data obtained from the question. This includes the following:
Acceleration due to gravity (g) = 1.67 m/s2
Length (L) = 8.35m (the length remains the same)
Period (T) =?
The period can be obtained as follow:
T = 2π√(L/g)
T = 2π√(8.35/1.67)
T = 14.05 secs
Therefore, the period on the moon is 14.05 secs
Answer:
a)
m/s
b)
Angular frequency = 
Explanation:
As we know

q is the charge on the electron =
C
B is the magnetic field in Tesla =
T
r is the radius of the circle =
m
mass of the electrons =
Kg
a)
Substituting the given values in above equation, we get -
m/s
b)
Angular frequency =
