A custodian pushes a 138 kg box across a level floor. The box moves at a constant velocity. The custodian pushes horizontally on the box with a force of 853 Newtons, what must be the friction force experienced by the box in Newtons?

Iron reacts with sulfur to form iron sulfide. if 60 grams of iron reacts with sulfur to produce 90 grams of iron sulfide, how much sulfur has been used in the chemical reaction?

Astone is dropped with no initial velocity from the top of a cliff and hits the ground a time of 3.9 s later. what is the height of the cliff, in units of meters? you may assume that air resistance is negligible. give the answer as a positive number question 15 a figure skater is rotating at a rate of 200 revolutions per minute. what is the angular speed, in units of rad/s? 200 o 20.9 12000 o 3.33

Determine the maximum r-value of the polar equation r =3+3 cos 0