A current of 6.67 A in a solenoid of length 13.6 cm creates a 0.373 T magnetic field at the center of the solenoid. How many turns does this solenoid contain?

The value is  

Explanation:

From the question we are told that

   The current is  

  The length is  

  The magnetic field is  

Gnerally the number of turn per unit length is mathematically represented as

Here is the permeability of free space with value  

So

=>    

=>    

Generally the number of turn is mathematically represented as

=>  

=>  

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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here we know that ball will drop down by total distance 3.2 m

so here we know that

now using kinematics

now in the same time it will cover horizontal distance of 0.75 m

so speed of the ball will be