Are cosmic rays and gamma rays invisible or do they have color?

Polly is pushing a box across the floor with a force of 30 n. the force of gravity is –8 n, and the normal force is 8 n. which value could describe the force of friction if polly could not move the box?

Of is j/kg·k. if a 2.6 kg of isk to k, is ?

What is the gravitational attraction between a dating couple whose centers of mass are 0.630 m apart if the boy weighs 715 n and the girl weighs 465 n?