m = 5 kg
a = 2 m/s²
to find the force that accelerates the 4 kg object @ 2 m/s²
F = ma = 5 kg x 2 m/s² = 10 N
To find what acceleration 10 N would give a 20 kg object
a = F/m = 10 N/20 kg = 0.5 m/s
Answer:

Explanation:
Given that

re= 46 cm
Vp= 180 m/s
We know that


So

Now by putting the all given values in the questions


So the average electric field is
.
Answer:
The friction force is 250 N
Explanation:
The desk is moving at constant velocity. This means that its acceleration is zero: a = 0. Newton's second law states that the resultant of the forces acting on the desk is equal to the product between mass (m) and acceleration (a):

In this case, we know that the acceleration is zero: a = 0, so also the resultant of the forces must be zero:
(1)
We are only interested in the forces acting along the horizontal direction, since it is the direction of motion. There are two forces acting in this direction:
- the pull, forward, F = 250 N
- the friction force, backward, 
Given (1), we have

So the force of friction must be equal to the pull:

I believe it is humans or animals cause duh what else gets sick