What height does a frictionless playground slide need so that a 35 kg child reaches the bottom at a speed of 5.3 m/s

c, 1a hope this

b.a device that inputs heat into a cool object

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.