Some energy is free but other types must be bought true or false

A roller coaster with a potential energy of 235,200 J sits at the top of a 30 m high hill. What is the mass of the roller coaster? (Formula: PE = mgh)

At what speed does a falling hailstone travel? Does the speed depend on the distance that the hailstone falls?

For the reaction shown below, which statement is correct? Ba (OH) 2 + 8H20 + 2NH4NO3 + heat?10H2O + 2NH3 + Ba (NO3) 2 A. The products contain more energy. B. The reactants contain more energy. C.

A certain radio wave has a frequency of 2.0x10^6 Hz. what is its wavelength?

A monatomic ideal gas undergoes an isothermal expansion at 300 k, as the volume increased from 0.010 m3 to 0.040 m3. the final pressure is 130 kpa. what is the change in the internal (thermal) energy of the gas during this process? (r = 8.

Total internal reflection occurs only if

A radioactive nucleus at rest decays into a second nucleus, an electron, and a neutrino. the electron and neutrino are emitted at right angles and have momenta of 9.80 ✕ 10-23 kg·m/s, and 5.70 ✕ 10-23 kg·m/s, respectively.

A child is sliding down a slide at the playground. Is the mechanical energy conserved? Why or why not? The mechanical energy is conserved. There is as much KE at the end as there was PE at the beginning. The mechanical energy isn't conserved.

Which term refers to the rate at which the velocity of a moving object changes? A. acceleration B. displacement C. resonance D. turbulance

This is a number, as of years, days, minutes, or seconds representing such an interval. The SI standard unit of this is the second.