An 85 kg man is two-thirds the way up a an 8 m ladder that rests against a smooth wall (smooth means no friction) and has a mass of 25 kg and makes an angle with the ground of 50°. Find the force of friction on the ground.

Who was the first scientist to measure speed as distance over time?

Iron is a transition metal with multiple oxidation numbers. (answer the following) a. what is the iron (ii) ion? how does it differ from the iron (iii) ion? b. if iron were to bond with oxygen, predict the formula for each oxidation number of iron. c. how would each formula be named?

Why does the liquid rise up through the dip tube when the valve is open