Aramp 20 m long and 4 m high is used to lift a heavy box. a pulley system with 4 rope sections supporting the load is used to lift an identical box to a height of 4 m. if friction is ignored, the ramp requires a to lift the load.

Photoelectrons with a maximum speed of 6.50 x 107 m/s are ejected from a surface in the presence of light with a frequency of 6.75 x 1014hz. if the mass of an electron is 9.10 x 10-31 kg, calculate in joules the maximum kinetic energy of a single electron. 3.84 x 10-15 j 1.92 x 10-15 j 5.92 x 10-23 j 3.07 x 10-16 j

The charge on an electron is 1.60218 × 10−19 c and its mass is 9.10939 × 10−31 kg. how strong a magnetic field must be experienced by the electron if its path is a circle of radius 5.5 cm? answer in units of t.

Why is the energy that results from a roller coaster's position at the top of a hill referred to as potential energy?