Answer:
Explanation:
1. Mechanical waves require material medium for their propagation while electromagnetic waves do not require material medium for their propagation.
2. Mechanical waves can either be transverse or longitudinal while electromagnetic waves are transverse.(Transverse waves are waves in which the vibration of the particules of the medium is perpendicular to the direction of the motion of wave. E.g water waves, waves of a plucked string and all electromagnetic waves RIVUXG . Longitudinal waves are waves whose vibration are parallel to the direction of the motion of the medium e.g waves in strings, sound waves.e.t.c)
The centripetal force exerted on the automobile while rounding the curve is 
<u>Explanation:</u>
given that

Objects moving around a circular track will experience centripetal force towards the center of the circular track.

It really depends on the angle where you look at it from and what type of glass/shape they are in. Mine always appeared pretty close even when it wasn't.
Source: Had 5 fish of my own.
Have a lovely day! ~Pooch ♥
Answer:
792 J
Explanation:
The total energy of the ball is E = U + K where U = potential energy = mgh and K = kinetic energy = 1/2mv²
E = mgh + 1/2mv² where m = mass of ball = 2.0 kg, g = acceleration due to gravity = 9.8 m/s², h = height of building = 20.0 m, v = initial velocity of ball = 20.0 m/s.
So, substituting the values of the variables into E, we have
E = mgh + 1/2mv²
= 2.00 kg × 9.8 m/s² × 20.0 m + 1/2 × 2.00 kg × (20.0 m/s)²
= 392 J + 400 J
= 792 J