Given :
An electron moving in the positive x direction experiences a magnetic force in the positive z direction.
To Find :
The direction of the magnetic field.
Solution :
We know, force is given by :

Here, q = -e.

Now, for above condition to satisfy :

So, 
Therefore, direction of magnetic field is negative y direction.
Hence, this is the required solution.
 
        
             
        
        
        
Answer:
 yes
Explanation:
I would say yes because it's exerting some type of force as it reacts to the stick to make it jump straight in an upwards direction
 
        
                    
             
        
        
        
Answer:

Explanation:
For this problem, we can use Boyle's law, which states that for a gas at constant temperature, the product between pressure and volume remains constant:

which can also be rewritten as

In our case, we have:
 is the initial pressure
 is the initial pressure
 is the initial volume
 is the initial volume
 is the final pressure
 is the final pressure
Solving for V2, we find the final volume:

 
        
             
        
        
        
Answer:

Explanation:
The heaviside function is defined as:

so we see that the Heaviside function "switches on" when , and remains switched on when
, and remains switched on when 
If we want our heaviside function to switch on when  , we need the argument to the heaviside function to be 0 when
, we need the argument to the heaviside function to be 0 when 
Thus we define a function f:

The  term inside the heaviside function makes sure to displace the function 5 units to the right.
 term inside the heaviside function makes sure to displace the function 5 units to the right. 
Now we just need to add a scale up factor of 240 V, because thats the voltage applied after the heaviside function switches on. ( when
 when  , so it becomes just a 1, which we can safely ignore.)
, so it becomes just a 1, which we can safely ignore.)
Therefore our final result is:

I have made a sketch for you, and added it as attachment.  
 
        
             
        
        
        
Answer:
3.6km South East
Explanation:
Displacement is the shortest distance between the starting point and the ending point and the direction it is displaced in. To calculate the displacement we can use the pythagoras theorem because the 3km East and the 2km south form the two shorter sides of a right angled triangle between the starting and ending points. So, the displacement is the length C of the triangle which we can calculate as follows:
Pythagoras Theorem:
a^2+b^2=c^2 
(2)^2+(3)^2=c^(2)
4+9=c^2
Square root 13 = c
c=3.6km (1dp)
The total displacement is 3.6km and is in the approximate direction of South East (because he travelled east and south). 
Hope this helped!