A60 kg crate is dragged across a floor by pulling on a rope attached to the crate and inclined 18° above the horizontal. (a) if the coefficient of static friction is 0.51, what minimum force magnitude is required from the rope to start the crate moving? (b) if μk = 0.26, what is the magnitude of the initial acceleration (m/s^2) of the crate?

More solar radiation is absorbed by earth’s surface than by

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.

In the circuit, the switch s has been open for a long time and r = 125 kohm. it is then suddenly closed. (a) determine the time constant before the switch is closed. s (b) determine the time constant after the switch is closed. _ s (c) let the switch be closed at t = 0. find the current in the switch as a function of time. (use t for time. express your answer in milliamps and seconds.) i(t) =_