A heat engine has a thermal efficiency of 0.46. During each cycle, it absorbs 780 J of heat from a high-temperature reservoir. How much waste heat does it discard each cycle. A) 420 J
B) 200J
C) 780 J
D) 360 J

the body's situation won't change the forces are equal opposit and on the same body

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.