Using the equation

we can observe that you have to apply a non-zero net force to an object in order to make it accelerate. In fact, if the net force is zero you have

Since we're assuming 
Now, if the 12N force is applied, the object moves with a constant speed. A constant speed means no acceleration, since by definition the acceleration is a change in speed.
If this sounds counterintuitive to you (why I'm applying a force but I have to acceleration?) think of when we drive a car: even if you want to keep your speed constant, you still have to use the gas pedal, just enough so that the push of the motor balances exactly the road/wheels friction. If you give less gas, the friction becomes stronger, and the car slows down. If you give more gas, the motor push becomes stronger, and the car accelerates.
Back to your exercise: constant speed means to acceleration, so the net force must be zero. This implies that the friction force is exactly 12N.
If the force is increased to 18N, there will be a net force of 6N pushing the object, causing it to accelerate. Using again the same equation of before, and plugging the 3kg mass in the equation, we have

So, the object moves with constant acceleration and initial speed of 10m/s for 0.2 seconds. It's final speed will be

The false statement would be :
C. constructive interference occurs when the crest of one wave overlaps the trough of another and their individual effects are reduced or cancelled out.
Constructive interference should be when the crest of one wave overlaps another and their individual effects are add up, becoming a single wave of increased amplitude<span />
When the sun, moon, and Earth are lined up (during a new or full moon), the solar tide adds to the lunar tide to produce extremely high tides and very low tides, both of which are known as spring tides.
- Basically describes a situation in astronomy where three celestial bodies align in a straight line as part of a gravitational system. The phrase is frequently used to describe how the Sun, Moon, and Earth are in a straight line.
- The moon is responsible for causing high and low tides. The tidal force is produced by the moon's gravitational pull. Earth and its water protrude outward on both the side that is closest to and farthest from the moon as a result of the tidal force. These watery peaks are high tide
To know more about high tides
brainly.com/question/11243732
#SPJ4
Answer:
A plain mirrior is a mirrior with flat reflective surface.
hope it is helpful for you.
Answer:
4.0 m/s
Explanation:
The motion of the diver is the motion of a projectile: so we need to find the horizontal and the vertical component of the initial velocity.
Let's consider the horizontal motion first. This motion occurs with constant speed, so the distance covered in a time t is

where here we have
d = 3.0 m is the horizontal distance covered
vx is the horizontal velocity
t = 1.3 s is the duration of the fall
Solving for vx,

Now let's consider the vertical motion: this is an accelerated motion with constant acceleration g=9.8 m/s^2 towards the ground. The vertical position at time t is given by

where
h = 4.0 m is the initial height
vy is the initial vertical velocity
We know that at t = 1.3 s, the vertical position is zero: y = 0. Substituting these numbers, we can find vy

So now we can find the magnitude of the initial velocity:
