If mike does 25.5 j of work lifting a book 1.5 m onto a shelf what is the mass of the book in kilograms

What do we mean by the event horizon of a black hole?

Abeam of light shining from water to air strikes the surface at an angle greater than 48 degrees and produces total internal reflection. if the incident beam is at a 50 degree angle what angle is the reflected beam 13 25 50 100

An electron with a charge of -1.6 × 10^-19 coulombs experiences a field of 1.4 × 10^5 newtons/coulomb. what is the magnitude of the electric force on this electron due to this field? a. 1.6 × 10^-3 newtons b. 1.4 × 10^24 newtons c. 2.2 × 10^-14 newtons d. 7.4 × 10^-13 newtons e. 4.5 × 10^14 newtons