D. The direction of the force is toward the center of the object's circular path.
I think its true i dont kno for sure
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.
Explanation:
Precision represents that how close the different measurements of the sample one take are to one another.
- One can increase the precision in lab by paying attention to each and every detail.
- Usage of the equipment properly and also increasing the sample size.
-
Ensuring that the equipment is calibrated properly. They should be clean and functioning. Using equipment which is not functioning correctly can cause results to swing wildly and also bits of the debris stuck to the equipment can influence the measurements of the mass and the volume.
- Each measurement must be taken multiple times, especially if experiments in which combining of the substances in specific amounts is involved.
Answer:

Explanation:
information we know:
Total force: 
Weight: 
distance: 
vertical component of the force: 
-------------
In this case we need the formulas to calculate the components of the force (because to calculate the work we need the horizontal component of the force).
horizontal component: 
vertical component: 
but from the given information we know that 
so, equation these two
and 

and we know the force
, thus:

now we clear for 

the angle to the horizontal is 15.466°, with this information we can calculate the horizontal component of the force:


whith this horizontal component we calculate the work to move the crate a distance of 4 m:

the work done is W=173.48J