21. Fig. 4.1 shows part of a fairground ride with a carriage on ralls.
3.9 m
30°
Fig. 4.1
The carriage of mass 500 kg is travelling towards a slope inclined at 30° to the horizontal.
The carriage has a kinetic energy of 25 kJ at the bottom of the slope. The carriage comes to
rest after travelling up the slope to a vertical height of 3.9 m.
a) Show that the potential energy gained by the carriage is 19 kJ.
g=9.8

b) Calculate the work done against the resistive forces as the carriage moves up the slope.
work done = ...​

Which of the following is not a part of the respiratory system? a. pharynx b. trachea c. pancreas d. larynx hurrim timed

Search coils and credit cards. one practical way to measure magnetic field strength uses a small, closely wound coil called a search coil. the coil is initially held with its plane perpendicular to a magnetic field. the coil is then either quickly rotated a quarter-turn about a diameter or quickly pulled out of the field. (a) derive the equation relating the total charge q that flows through a search coil to the magnetic-field magnitude b. the search coil has n turns, each with area a, and the flux through the coil is decreased from its initial maximum value to zero in a time ∆t. the resistance of the coil is r, and the total charge is q = i∆t, where i is the average current induced by the change in flux. (b) in a credit card reader, the magnetic strip on the back of a credit card is rapidly “swiped” past a coil within the reader. explain, using the same ideas that underlie the operation of a search coil, how the reader can decode the information stored in the pattern of magnetization on the strip. (c) is it necessary that the credit card be “swiped” through the reader at exactly the right speed? why or why not?

I'm thinking it's 2 you are asked to explain the earth's magnetic field. which is the best reply? 1. the earth's magnetic south is similar to the north pole of a magnet. 2. the earth's core has a strong magnetic charge similar to the south pole of a magnet. 3. the earth's geomagnetic south is similar to the south pole of a magnet. 4. the earth's magnetic charge is not centered at either pole; it varies based on location.