Zeros that follow non-zeros numbers and are also to the right of a decimal point are significant

The coefficient of friction is a number that represents the resistance to sliding between two in contact with one another.

Looking at this barometer, is the air pressure high or low? what type of weather would you expect? high, bad low, bad high, good low, good

Under the action of a constant force an object accelerates at 7.8 m/s2. what will the acceleration be if (a) the force is halved? (b) the object's mass is halved? (c) the force and the object's mass are both halved? (d) the force is halved and the object's mass is doubled?