A trout was swimming in a river. The trout swam 7,000centimeters directly upstream at a constant velocity. It swam that distance in 0.7minutes. What was its velocity?

What would the difference of spectral lines emitted by hydrogen gas in distant galaxies which is normally found at a wavelength of 21 cm on earth, be observed at 21.1 centimeters?

Aknife blade is a(n) a. lever b. screw c. wedge d. inclined plane

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?