# A toy train is pushed forward and released at 2.0m with a speed of 1.0m/s. it rolls at a steady speed for 2.0s, then one wheel begins to stick. the train comes to a stop at 5.0m from the point at which it was released. what is the train's acceleration after its wheel begins to stick?

Recall that

where

- is the final velocity of the train; 0 in this case, because the train eventually stops

- is the initial velocity of the train; 1.0 m/s in this case, because this initial velocity refers to velocity it starts with after one of the wheels gets stuck, and the train is initially traveling at a constant speed of 1.0 m/s

- is the acceleration we want to find

- is the change in the train's position; 5.0 m in this case

So we have

## Related Questions

Describe the evolution of a star with a mass like that of the Sun, from the main-sequence phase of its evolution until it becomes a white dwarf.

After the main sequence phase ends, the star will evolve toward the upper-right area of the H-R diagram as its core contracts and the outer layers expand. It then becomes a red giant and will continue to expand its outer layers. This causes its luminosity to increase, the star's size can become more than 100 times its main-sequence radius. Eventually, the contracting core reaches a temperature of 100 million K, which leads to the explosive ignition of helium. When the star stabilizes, it will lose some of its outer layers as it becomes smaller, and moves back toward the main sequence region of the H-R diagram. The star will continue to fuse helium into carbon and oxygen, but for a time much shorter than the time on the main sequence.

Eventually, the core will be depleted of helium, and the star once more evolves toward the upper-right area of the H-R diagram as the core contracts and the outer layers expand to an even greater extent. The outer layers of the star will be gradually blown out into space by the strong winds during this period. This leads to the formation of a planetary nebula out of the outer layers of the star. The remaining mass of the star in the core continues to contract and will eventually become a white dwarf.

Three resistors are connected in series across a 15-V power supply. If the potential drops across resistors 1 and 2 are 4.1 volts and 3.1 volts, what is the exact potential drop (in volts) across resistor 3?

7.8 V

Explanation:

When resistors are connected in series, they are connected in the same branch of the circuit. This means that the current flowing each resistor is the same, while the sum of the voltage drops across each resistor is equal to the potential difference of the power supply:

In this circuit we have:

V = 15 V

So, the voltage drop across resistor 3 is

How does the current model of the solar system differ from the first model of the solar system?