Answer:
c. The force exerted by X on Y is F to the right, and the force exerted by Yon X is F to the left.
Explanation:
If we take both objects as one single system, during the collision, assuming no external forces acting, the only forces present are the one that object X exerts on object Y, and the force that object Y does on object X.
These two forces, according to Newton's 3rd Law, form an action-reaction pair, and consequently, are equal in magnitude, acting in opposite directions.
As the object X is moving to the right, the force that produces, (F), is in the same direction (on Y), while for object Y, moving to the left, the force that produces (F also in magnitude) is in the same direction (on X), so the right answer is c.
The effect of the forces is different, due to masses are different, according Newton's 2nd Law.
<h2>
Answer: B. Gravitational potential energy </h2>
Explanation:
<em>The gravitational potential energy is the energy that a body or object possesses, due to its position in a gravitational field.
</em>
That is why this energy depends on the relative height of an object with respect to some point of reference and associated with the gravitational force.
In the case of the <u>Earth</u>, in which <u>the gravitational field is considered constant</u>, the value of the gravitational potential energy 
will be:
Where 
is the mass of the object, 
the acceleration due gravity and 
the height of the object.
As we can see, the value of is directly proportional to the height.
1. a. longitudinal waves.
There are two types of waves:
- Transverse waves: in transverse waves, the oscillations of the wave occur in a direction perpendicular to the direction of propagation of the wave
- Longitudinal waves: in longitudinal waves, the oscillations of the waves occur parallel to the direction in which the waves are travelling.
So, these types of waves are called longitudinal waves.
2. d. a medium
There are two types of waves:
- Electromagnetic waves: these waves are produced by the oscillations of electric and magnetic field, and they can travel both in a medium and also in a vacuum (they do not need a medium to propagate)
- Mechanical waves: these waves are produced by the oscillations of the particles in a medium, so they need a medium to propagate - therefore, the correct choice is d. a medium
3. a. AM/FM radio
Analogue signals consist of continuous signals, which vary in a continuous range of values. On the contrary, digital signals consist of discrete signals, which can assume only some discrete values. For AM and FM radios, signals are transmitted by using analogue signals.
The answer is D. Blackbody radiation. The piece of iron glows red because its temperature is around 1000 K, then yellow because its temperature is around 2800 K, and then white because its temperature is around 5500K. This shows that the spectrum of the radiation is determined by absolute temperature, as when the temperature of a blackbody radiator increases, the peak of the radiation curve moves to shorter wavelengths.
The acceleration produced in a body is always in the direction of the resultant force acting on the body. Therefore, we may determine the horizontal acceleration using the horizontal force applied. To do this, we may apply the mathematical form of Newton's second law:
Force = mass * acceleration
acceleration = force / mass
Substituting the values,
a = 100 / 0.15
a = 666.7 m/s²
The acceleration of the hockey puck is 670 m/s²
