Is this a book and most likely because the were cute
Answer:
a) 
Explanation:
Given paraeters are:
R = 25 cm
d = 4.7 mm
f = 60 Hz
= 160 V
a) 
Where
Hz and
V

For 

Since 

From Ampere's Law:
where 
So at
,

For maximum B, cos(2πft) = 1. Hence,
T
b) From r = 0 to r = R = 0.025 m, by Ampere's Law, the equation will be:

From r = R = 0.025 m to r = 0.1 m, by Ampere's Law, the equation will be:

The plot is given in the attachment.
Answer:
1.28 m
Explanation:
Given;
Radius, r = 1.5 cm = 0.015 m
Time, t = 19 s
Average angular speed = 4.5 rad/s
Consider a point when the tape is moving at a constant velocity along the circumference of the circular reel of radius r. The linear velocity v at this point is given by;
v = rω ----(1)
Where
v is the linear velocity of the circular motion
r is the radius of the reel
ω is the the angular velocity.
At a point the tap undergoes a linear motion before passing round the reel of the cassette. The linear velocity v at this point is given by;
v = L/t ----(2)
where;
v is the velocity of the linear motion
L is the length of the tape (distance covered by the tape)
t is the time taken
Equating equation(1) and equation (2)
L/t = rω
L = rωt
Substituting the given values,
L = 0.015 × 4.5 × 19
L = 1.2825 m
L = 1.28 m
With total velocity
, the horizontal component of velocity is

Then the horizontal displacement over the first minute is
