Answer:
Here we need to make parallel connection of two 80 ohm resistors to achieve 40 ohm net resistance.
Explanation:
As we know that the resistances in series add up directly and here we are given with only the resistors of 80 Ω.
So when we connect two resistors of 80 ohm in parallel we get the resultant of 40 ohm.
Mathematically:
gives us the only combination of two resistors in parallel.
Answer:
The unbalanced force that caused the ball to stop was friction
Explanation:
As Newton's second law states, the acceleration of an object is proportional to the net force applied on the object:
therefore, in order to move at constant speed, an object should have a net force of zero (balanced forces) acting on it.
In this case, the ball slows down and eventually comes to a stop: it means that the ball is decelerating, so there are unbalanced forces (net force different from zero) acting on it. The unbalanced force acting on the ball is the friction: friction is a force against the motion of the object, which is due to the contact between the surface of the ball and the surface of the street, and this force is responsible for slowing down the ball.