Atoms of element A decay to atoms of element B with a half-life of 20,000 years. If there are 10,000 atoms of A to begin with (and 0 atoms of B), how long will it take for there to be 2,500 atoms of A?

A lightbulb glows brightly when it is connected across a certain battery. The battery will maintain a constant potential difference even as its output current increases.

A 2000 kg car is parked at the top of a 30 m high hill. what is its potential energy

1. How does changing the voltage in a circuit affect the current in the circuit? 2. What is the impact of adding more light bulbs in series? 3. In the series circuit, is the current constant throughout the circuit, or does it vary?

Which of the following is true concerning nuclear fusion? a. it generally releases more heat than nuclear fission. b. it involves the splitting of a nucleus into smaller fragments. c. it can occur at room temperature. d. all of the above

You do 174 J of work while pulling your sister back on a swing, whose chain is 5.10 m long, until the swing makes an angle of 32.0° with the vertical. What is your sister's mass?

What is the mechanical advantage of a pulley?

What kind of movement does the heat within the core and mantle directly generate?

Explain why Newton's first law of motion can be difficult to observe in moving objects?

No force is necessary to

A boat has a mass of 4040 kg. Its engines generate a drive force of 4660 N due west, while the wind exerts a force of 880 N due east and the water exerts a resistive force of 1400 N due east. Take west to be the positive direction.