If force = mass x acceleration, what is the force applied to a 20 kg rock that is acceleration at a 20 m/s^2? a.)20 n b.)0 n c.)40 n d.)10 n

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

Ascientific blank must be testable and capable of being proven false?

Atrain is traveling at 30.0 m/s relative to the ground in still air. the frequency of the note emitted by the train whistle is 262 hz. the speed of sound in air should be taken as 344 m/s. what frequency (f approach) is heard by a passenger on a train moving at a speed of 18.0 m/s relative to the ground in a direction opposite to the first train and approaching it? what frequency (f recede) is heard by a passenger on a train moving at a speed of 18.0 m/s relative to the ground in a direction opposite to the first train and receding from it?