# Need your help

- How is electric potential energy similar to gravitational potential energy? How is it different? Where will an electron bound in an atom and have the largest electrical potential energy?
- What is a transformer? Explain how a transformer works including specific details on step up and step down transformers.
- Write at least 4 to 5 sentences on the different measurements that helped to calculate the speed of light. There are 3 specific experiments mentioned in your textbook.
- Three equal-sized holes are drilled at the top, middle, and bottom of the side of a barrel filled with water. Describe the path (which is NOT speed) of water coming from each hole. Explain why water from the bottom home comes out the fastest
- What caused magnetic fields? What happens If you keep breaking a magnet in two until you reach a single atom?
- What is an electric motor? Explain its operation.
- State Hooke’s law. A spring will stretch 12 cm when a 250-g mass is hung on it. If the 250-g mass is hung on two identical springs, hung sided by side, and both support the 250-g mass, how much will each spring stretch. EXPLAIN.
- Use 4 to 5 complete sentences, explain the concepts of beats and how beats are produces. Please provide at least 2 examples.
- Why do atoms have relatively the same size even though they may have widely different masses?
- What is the period of a soundwave whose wavelength is 20.0 m? Use values from the book and show ALL of your work.
- A 60-V potential different is applied across a parallel combination of a 10-ohm and 20-ohm resistor. What is the current in the 10-ohm resistor? Show your work.
- What is the power dissipated by a toaster that has a resistance of 60 ohms and is plugged into a 120-V outlet? Show your work.
- A step up transformer has 250 turns on its primary and 500 turns on it secondary. When the primary is connected to a 200 V and the secondary is connected to a floodlight that draws 5A, what is the power output? Please show ALL of your work.
- What is the mass of air in a room that has dimensions of 10m x 20m x 4 m? Use values from the book to show your work.
- About how much pressure do the feet of a 6000-kg elephant exert on the ground? Assume each foot has an area of 0.10 square meter. Please show all your work.
- The temperature of an object is raised by 90
^{o}C^{ }. This is equivalent to what increase in its absolute temperature? - A supersonic aircraft produces a shock wave that describes a 30
^{o}angle. What happens to the angle of the cone as the aircraft travels faster? - A 2.0-ohm resistor is connected in a series with a 20.0 -V battery and a three-branch parallel network with branches whose resistance are 8.0 ohms each. Ignoring the battery’s internal resistance, what is the current in the batter? Show your work.
- Gas A is composed of diatomic molecules (two atoms to a molecule) of a pure element. Gas B is composed of monoatomic molecules (one atom to a molecule) of another pure element. Gas A has three times the mass of an equal volume of gas B at the same temperature and pressure. How do the atomic masses of elements A and B compare?
- Consider a model steel bridge that is 1/100 the exact scale of the real bridge that is to be built.
- If the model bridge weighs 50 N, what will the real bridge weigh?
- If the model bridge does not appear to sag under its own weight, is this evidence the real bridge, built exactly to scale, will not appear to sag either?

- Calculate the water pressure in the pipes at the bottom of a high-rise building that is fed by reservoir 60 m above the roof top.
- The atmosphere does not ordinarily crush cans. However, it will crush a can after it has been heated, capped, and cooled. Explain why this happens. Be sure to use complete sentences
- When a 57-gram piece of aluminum at 100
^{o}C is placed in water, it loses 735 calories of heat while cooling to 30^{o}C. Calculate the specific health capacity of the aluminum. - Your classmate says that if all the molecules in a particular liquid had the same speed, and some were able to evaporate, the remaining liquid would not undergo cooling. Do you agree or disagree and what is your explanation to support your answer.
- Would it be correct to say the Doppler Effect is the apparent change in the speed of a wave due to the motion of the source? Be sure to fully explain your position using at least 3 complete content related sentences.
- The equation E=hf describes the energy of each photon in a beam of light. If Planck’s constant, h, were larger, would photons of light of the same frequency be more energetic or less energetic. Be sure to explain using at least 3 content related sentences.
- A radioisotope is place near a radiation detector, which registers 80 counts per second. Eight hours later, the detector registers five counts per section. What is the isotope’s half-life?
- Write the nuclear equation that describes the following process. Uranium-235 undergoes an alpha decay to produce thorium-231.
- If the uranium nucleus were split into three pieces of approximately the same size instead of two, would more energy or less energy be released? Defend your answer in terms of Figure 40.14 in your textbook.
- According to chapter 13 in the course textbook, describe the time it would take for Earth to orbit the collapsed sun if the sun collapsed into a black hole.