<span>which of those can we not get back once it has been used, the answer is oil or petroleum</span>
Answer:
5 ohms
Explanation:
Given:
EMF of the ideal battery (E) = 60 V
Voltage across the terminals of the battery (V) = 40 V
Current across the terminals (I) = 4 A
Let the internal resistance be 'r'.
Now, we know that, the voltage drop in the battery is given as:
Therefore, the voltage across the terminals of the battery is given as:

Now, rewriting in terms of 'r', we get:

Plug in the given values and solve for 'r'. This gives,

Therefore, the internal resistance of the battery is 5 ohms.
The net force is the 10N force and its direction is towards F2 force.
<h3>What is resultant force?</h3>
The resultant force or the net force is the actual force that acts on a body. We are told that the two forces act in opposite directions hence the net force is F2 - F1 = 30 N - 20 N = 10 N.
ii) The direction of this net force is going to be towards the 30N force.
iii) If the body does not move under the application of these forces then the F1 force must be reinforced by another force which balances it against the F2 force.
Learn more about net force:brainly.com/question/18031889?
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Answer:
none
Explanation:
Newton's first law says an object in motion will stay in motion at the same speed and direction unless acted upon by some force.
No force is necessary for the object to keep its speed and direction on a frictionless surface.
Explanation:
The small mass of lens in a DVD player accounts for small inertia of the lens. Hence, even on application of force of small magnitude, the lens is rapidly accelerated. Moreover, the small mass of lens also accounts for lower resistance to change in its motion and therefore, again can be rapidly accelerated back and forth.