A train rolls at a constant speed of 10 m/s across a horizontal track. A child standing on the flatbed of the train throws a ball so that it appears to move straight up to an observer standing next to the track. a) What is the horizontal speed of the ball relative to the observer?

b) What is the horizontal speed of the ball relative to the train?

C)If the ball is also thrown upward with a speed of 20 m/s, what is the overall Initial speed of the ball
relative to the train?

stands for electromotive force and it is measured in volts. despite its name, it is not actually the force in the sense of being a "pushing" or "pulling" (not measured in newtons).an equation that relates emf,  ℰ,  to a battery's terminal voltage, v, current, i, and internal resistance, r, is    ℰ = v + irin this case, the emf can be interpreted as a voltage—a difference in electric potential.i would not say that it would be considered an energy. if emf can be defined as the energy/work per a unit charge from a battery or other electric source, then it is not strictly energy.

All are great precautions but you can still lift lighter and different muscles in between hard workdays. this keeps other muscles not usually used in shape.

Answerthe force between the charges will be  f/9 (one-ninth of force f)explanationcoulomb's law relates the magnitudes  two point charges q₁ and q₂, the distance, r, between the charges, and the electrostatic force, f, between the two charges:     k represents coulomb's constant, k = 8.99×10⁹ n·m²/c².note that if we have r = 3r, then   

Idon't understand is there supposed to be a list or something if there is pm or add in under this message i will do my best to .