Sig figs are digits read directly from the measuring instruments plus one more digit which is By the observer

Big Al stands on a skateboard at a rest and throws a 0.5-kilogram rock at a velocity of 10.0 m / sec. Big Al moves back at 0.05 m/sec. What is the combined mass of Big Al and the skateboard?

What is the speed of sound for noise that travels 2 km in 5.8

A dragster starts from rest and travels 1/4 mi in 6.80 s with constant acceleration. What is its velocity when it crosses the finish line?

My reaction time was 0.7268 seconds the first time and 0.3883 the second time. What was yours

A physics book rests upon a level table

Explain where most of the mass of an atom is located. Also, explain why some particles that make up the atom do not contribute much to its mass.

A 2.5-kg book slides horizontally and falls from a shelf 3.0 m above the floor. How much work does the force of gravity do on the book as it falls 3.0 m?

An object rolls East at a steady speed of 12 m/s for 3 seconds. What distance did the object travel

Two identical billiards balls strike a rigid wall with the same speed but at diffrent angle and gets reflected with out change in speed what is (i) the ratio of the magnitudes implulse generated?

If light needs matter, how doe it move through space? this is my first question.