Fluorine-21 has a half-life of approximately 5 seconds. What percentage of the original nuclei would remain after 20 seconds

A uniform, solid metal disk of mass 6.00 kg and diameter 29.0 cm hangs in a horizontal plane, supported at its center by a vertical metal wire. You find that it requires a horizontal force of 4.28 N tangent to the rim of the disk to turn it by 3.

Which situation is an example of transferring heat by means of convection? A) the sun warming the earth B) the weather patterns outside C) you toasty-warm in some footy pajamas D) you accidentally grabbing the hot pan from the oven

A ___ is awarded to the opposing team when that team violently or dangerously charges a opponent. (in soccer) A) Goalie kick B) Indirect kick C) Direct kick D) Throw in

In a certain right triangle, the two sides that are perpendicular to each other have lengths h = 4.40 m and b = 8.70 m. What is the length of the third side of the triangle?

A new organism is discovered at the bottom of the ocean. A scientist is determining the composition of elements found in the tissues of the organism.

Electricity problem (coulomb's law)

An observer (O) spots a plane (P) taking off from a local airport and flying at a 29° angle horizontal to her line of sight and located directly above a tower (T). The observer also notices a bird (B) circling directly above her.

In order for convection to occur, you must have

Explain Newton's First Law for the following. If you walk across the room holding a ball, when should you drop it to ensure that it lands on a target? Before, after or when you are directly on the target?

In what way are all forms of potential energy the same?