The more mechanical efficiency there is, the work you have to put in​

Frost wedging occurs when water seeps into a crack in a rock, freezes, and causes the crack in the rock to widen. t or f

What is the acceleration of a spaceship that is initially at rest and then speeds up to 220 m/s in 20 seconds

The force acting on a beam was measured under the same operating conditions and a sample of 5 data points was collected. this process was repeated by 3 observers. the pooled standard deviations of these 3 data sets was 1.21. determine the true mean force using all pooled data (with a 95% probability). the result should look like this: true mean = mean +/- margin of error