28 Why is soft iron used for the core of an electromagnet? А Soft iron easily becomes a permanent magnet.
B Soft iron is a good electrical conductor.
с Soft iron is a poor thermal conductor.
D Soft iron loses its magnetism when the current in the coil is switched off.​

The man of mass m1 and the woman of mass m2 are standing on opposite ends of the platform of mass m0 which moves with negligible friction and is initially at rest with s = 0. the man and woman begin to approach each other. derive an expression for the displacement s of the platform when the two meet in terms of the displacement x1 of the man relative to the platform.

Astudent pushes a 60-n block across the floor for a distance of 10 m. how much work was done to move the block

How much work would it take to move a coulomb charge across a 4 volt potential difference?