Answer:

Explanation:
<u>Motion With Constant Acceleration
</u>
It's a type of motion in which the velocity of an object changes uniformly over time.
The equation that describes the change of velocities is:

Where:
a = acceleration
vo = initial speed
vf = final speed
t = time
Solving the equation for a:

The ball starts at rest (vo=0) and rolls down an inclined plane that makes it reach a speed of vf=7.5 m/s in t=3 seconds.
The acceleration is:


<h2>Answer: decreasing</h2>
An RC circuit is an electrical circuit composed of resistors and capacitors, where the charging time
of the circuit is proportional to the magnitude of the electrical resistance
and the capacity
of the capacitor.
As shown below:
In this context, the electrical resistance is the opposition to the flow of electrons when moving through a conductor.
Therefore:
<h2>When a capacitor is being charged in an RC circuit, the current flowing through a resistor <u>decreases</u>.</h2>
And the correct option is b.
Answer:

Explanation:
According to the free body diagram, in this case, we have:

Recall that the force of friction is given by:

Replacing and solving for the coefficient of kinetic friction:

We have an uniformly accelerated motion. Thus, the acceleration is defined as:

Finally, we calculate
:

Answer:

Explanation:
Power is defined as the energy produced (E) per unit of time (t):

This means that the energy produced in the Sun each second (1 s), given the power
, is

Each p-p chain reaction produces an amount of energy of

in order to get the total number of p-p chain reactions per second, we need to divide the total energy produced per second by the energy produced by each reaction:

The output waveforms after passing through the transformer actually depend on the type of transformer used. It could either be a step-up transformer (steps voltage up), or a step-down transformer (steps voltage down). Both transformers have an output voltage in a form of a sine wave.