Susan's 12.0 kg baby brother paul sits on a mat. susan pulls the mat across the floor using a rope that is angled 30∘ above the floor. the tension is a constant 29.0 n and the coefficient of friction is 0.180. use work and energy to find paul's speed after being pulled 2.70m .express your answer with the appropriate units.

The boy of mass 30 kg is at r1= 2 meters from the fulcrum. of the girl is 45 kg, at what r2 must she sit so that they are balanced ?

(a) calculate the number of electrons in a small, electrically neutral silver pin that has a mass of 10.0 g. silver has 47 electrons per atom, and its molar mass is 107.87 g/mol. (b) imagine adding electrons to the pin until the negative charge has the very large value 1.00 mc. how many electrons are added for every 109 electrons already present

Aboy with a mass 25 kg climbs into a small tree. he sits on a branch that is 2.o m above to the ground.what is his gravitational potential energy above the ground?