Answer:Due to change in direction
Explanation:
Given
Initially train has traveled a 100 km in North and after exchanging some railroad cars, it traveled 100 in south.
The velocity of the train changes as it direction of motion changes. Velocity is the vector quantity which require direction and magnitude for its reperesentation.
 
        
             
        
        
        
Answer:
a)
b) north edge will rise up
Explanation:
torque on the coil is given as 

where N is number of loop =  9 loops
i is current = 7.80 A
-B -earth magnetic field = 
A- area of circular coil


A =0.015 m2
 PUTITNG ALL VALUE TO GET TORQUE


 
b) north edge will rise up
 
        
                    
             
        
        
        
Answer:
It needs attractive force from the strong nuclear interaction to counter the electrostatic repulsion between the protons.
Explanation:
It has to counter 
 
        
             
        
        
        
Answer:
Fundamental frequency is 200 Hz.
Explanation:
It is given that,
Frequency of the 3rd harmonic is 600 Hz.
Let f is the fundamental frequency. We need to find the value of f. The frequency of third harmonic is given by :

So, fundamental frequency f is equal to :
f = 200 Hz
So, the fundamental frequency of the harmonics is 200 Hz. Hence, this is the required solution.