The electromagnet in a galvanometer

  concave means having an outline or surface that curves inward like the interior of a circle or sphere. so the mirror curves inward.

Answerapplying a direct current to a non magnetic material in order to create a electromagnetic field; plz check first good luck;

The figure is missing but we can answer anyway.the correct answer is "releasing the string". in fact, when the person is holding the bow and the arrow, the kinetic energy of the arrow is still zero (because the arrow is not moving). the moment the arrow is released, it acquires a velocity v, so its kinetic energy will become different from zero: where m is the mass of the arrow and v its velocity.  all the other options, instead, do not increase the kinetic energy of the system: -  pulling farther back on the string : this will just increase the elastic potential energy of the system-  holding the arrow higher: this will increase the gravitational potential energy of the system (which is given by u=mgh, where h is the height above the ground)-  decreasing the mass of the arrow: this will decrease the gravitational potential energy of the system (which is given by u=mgh, where m is the mass)

D.) a wheel barrow, due to the fact that where the weight is in the middle, the fulcrum is at the wheel, and the input force is at the other end