Does hot water or cold water boil faster is that repeated observations using models are controlled experiments

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

A17,250 kg rocket is pushed with a thrust of 6,450,284 n. what is the acceleration of the rocket?

This is the number of complete movements of a wave per second.