A48-kg boy is running on a track at 6m/s . what is the boys kinetic energy?

Abody of weight 60 kg is standing in a lift the lift going upward with a uniform velocity of 4.9 metre per second slows down and stops in two seconds then apparent weight of the body during the slow down process is

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

An object weighs 40n in air, weighs 20n when submerged in water and 30n when submerged in a liquid of unknown density. what is the density of the liquid?