Answer:

Explanation:
Given that,
The length of a string, l = 0.87 m
Speed of the ball, v = 3.36 m/s
We need to find the acceleration of the ball. The acceleration acting on the ball is centripetal acceleration. It is given by :

So, the acceleration of the ball is
.
Answer:
d) 1.2 mT
Explanation:
Here we want to find the magnitude of the magnetic field at a distance of 2.5 mm from the axis of the coaxial cable.
First of all, we observe that:
- The internal cylindrical conductor of radius 2 mm can be treated as a conductive wire placed at the axis of the cable, since here we are analyzing the field outside the radius of the conductor. The current flowing in this conductor is
I = 15 A
- The external conductor, of radius between 3 mm and 3.5 mm, does not contribute to the field at r = 2.5 mm, since 2.5 mm is situated before the inner shell of the conductor (at 3 mm).
Therefore, the net magnetic field is just given by the internal conductor. The magnetic field produced by a wire is given by

where
is the vacuum permeability
I = 15 A is the current in the conductor
r = 2.5 mm = 0.0025 m is the distance from the axis at which we want to calculate the field
Substituting, we find:

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 