Answer:
changing the polarity or direction of the battery changes the sign of the voltage and the current
Explanation:
The sign of current and voltage are due to established conventions.
The way that a DC circuit with negative current values is by changing the polarity of the power source or by inverting the battery, this creates that the electrons move in the opposite direction
Changing the battery also changes the direction of the power difference, since the potential from positive to negative, in most cases negative is assigned a potential of zero volts
In summary, changing the polarity or direction of the battery changes the sign of the voltage and the current
The motion of the ball on the vertical axis is an accelerated motion, with acceleration

The following relationship holds for an uniformly accelerated motion:

where S is the distance covered, vf the final velocity and vi the initial velocity.
If we take the moment the ball reaches the maximum height (let's call this height h), then at this point of the motion the vertical velocity is zero:

So we can rewrite the equation as

from which we can isolate h

(1)
Now let's assume that

is the initial velocity of the first ball. The second ball has an initial velocity that is twice the one of the first ball:

. So the maximum height of the second ball is

(2)
Which is 4 times the height we found in (1). Therefore, the maximum height of ball 2 is 4 times the maximum height of ball 1.
I think it’s 25 but I don’t know
Answer:
Workdone = 20 Joules
Explanation:
Given the following data;
Force = 10N
Extension, e = 4cm to meters = 4/100 = 0.04 meters
Workdone extension = 40cm to meters = 40/100 = 0.4 meters
To find the work done;
First of all, we would find the spring constant using the formula;
Force = spring constant * extension
10 = spring constant * 0.04
Spring constant = 10/0.04
Spring constant = 250 N/m
Next, we find the work done;
Workdone = ½ke²
Where;
k is the spring constant.
e is the extension.
Substituting into the formula, we have;
Workdone = ½ * 250 * 0.4²
Workdone = 125 * 0.16
Workdone = 20 Joules
Explanation:
hmm by the increasing the size of wheel and decreasing axle