Why were there 15 objects in our solar system originally classified as planets?

Initially, a particle is moving at 5.33 m/s at an angle of 37.9° above the horizontal. two seconds later, its velocity is 6.11 m/s at an angle of 54.2° below the horizontal. what was the particle's average acceleration during these 2.00 seconds in the x-direction (enter first) and the y-direction?

According to newtons universal law of gravitation, which would change the parh of the ball so it traces out widest curved path possible?

Infrared radiation has wavelengths that are shorter than visible light is part of the visible light spectrum has wavelengths that are longer than visible light has the same wavelengths as ultraviolet radiation