Độ lớn cảm ứng từ trong lòng một ống dây hình trụ có dòng điện chạy qua tính bằng biểu thức là A.

B.

C.

D.

F500 j of energy were added to 1 kg of each of these samples, which would experience the least temperature increase?

How does the amount of energy required to hold each proton and neutron in the nucleus compare to the energy released when they are removed?

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.