Isaac invents a machine that him mow the lawn. the work output of the machine is 10 foot-pounds. the work input is 20 foot-pounds. what is the efficiency of isaac's machine? i realy need with this plz me with thisi dont want to fail physics a.)1 b.)2 c.)5 d.)0.5

As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. when you push the platform, you compress the springs. you do an amount of work of 79.0 j when you compress the springs a distance of 0.230 m from their uncompressed length. (a) what magnitude of force must you apply to hold the platform in this position? (b)how much additional work must you do to move the platform a distance 0.230 m farther? (c) what maximum force must you apply to move the platform a distance 0.230 m farther?

Acar travels in reverse. it covers 150 meters in 12 seconds what is the velocity of the car what is the speed of the car

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) =_