If a system requires 150 j of input work and produces 123 J of output work, whats its effiency

Suppose you have 150. ml of a substance with density of 42.0 g/dm3. convert the volume from milliliters to liters to cubic decimeters, then determine the mass of the sample in grams.

sketch a graph of position vs. time for a person starting 0.4 m away and standing still. Include an explanation of your prediction

A cosmic ray electron moves at 6.5 x 106 m/s perpendicular to the Earth's magnetic field at an altitude where field strength is 1.24 10-5 T. What is the radius (in meters) of the circular path the electron follows? The charge of an electron is 1.

In 2012, Germans paid 1.65 Euros per liter of gasoline. At the same time, American prices were $3.90 per gallon. a. How much would one gallon of European gas have cost in dollars? b.

Astronomers have observed a small, massive object at the center of our Milky Way galaxy (see Section 13.8). A ring of material orbits this massive object; the ring has a diameter of about 15 light-years and an orbital speed of about 200 km>s.

T=2π√ (l/g) is dimensionally correct

A penny falls from a windowsill which is 25.0 m above the sidewalk. How much time does a passerby on the sidewalk below have to move out of the way before the penny hits the ground?

Show that the Newton has the units of mass times acceleration.

Light travels at 150000000km from the sun to earth in 8 minutes. What speed is this in Km/s

Electricity problem (coulomb's law)