ALWAYS use significant figure rules. Remember that these rules apply to all numbers that are measurements. An object is dropped from a platform 400 ft high. Ignoring wind resistance, what will its speed be when it reaches the ground?

7800 ft/s
12,800 ft/s
160 ft/s
89 ft/s

Rank the torques on the five doors shown in the figure above from least to greatest. note that the magnitude of all the forces is the same

Electromagnetic induction. a coil of wire contains n turns and has an electrical resistance r. the radius of each turn is a. initially, inside the coil there exists a uniform magnetic field of magnitude b0 parallel to the axis of the coil. the magnetic field is then reduced slowly. the current induced in the coil is i. how long does it take for the magnitude of the uniform field to drop to zero?

In science and physics what is the standard unit of measure for speed?