Answer:
0.027 J
Explanation:
The formula of the potential energy in electrostatic (U) is

The values given in the question are
Charge : q = 
Electric Field strength : E = 
Distance : d is 0.030 m
Insert in the formula , will give us

Further solving it

Which is the required answer.
Thanks
Answer:
Stationary
20N
Explanation:
From the graph, we see that the body traveling is on a fixed position. Therefore, it is a stationary body.
The graph given is a position - time curve.
This curve depict a body changing position with given time.
Since the line of the curve is on a single position, the body is not changing position with the passage of time therefore, it is a stationary object.
B. 20N
From Newton's third law of motion we understand that "action and reaction force are equal but oppositely directed".
Since the person is exerting a force of 20N on the balance.
So, the reaction force by the balance is 20N upward.
Answer:
Net force will be 4.875 N
Explanation:
We have given mass of the cart m = 1.5 kg
Initial velocity of the cart = 0.2 m/sec
And final velocity of the car = - 0.125 m/sec ( Negative direction is due to opposite direction )
Instant of time 
Change in momentum is given by

Now force is given by

Net force will be 4.875 N