Pls help ill mark u as a brainlist, but help pls​

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

Can someone me with my physics questions? i need correct answers only!

Why would an orange roll of your cafeteria tray if you stopped suddenly