Two objects (45.0 and 21.0 kg) are connected by a massless string that passes over a massless, frictionless pulley. the pulley hangs from the ceiling. find
(a) the acceleration of the objects and
(b) the tension in the string.

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

Aboy with a mass 25 kg climbs into a small tree. he sits on a branch that is 2.o m above to the ground.what is his gravitational potential energy above the ground?

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