Jacob is working on his physics portfolio and stands on a 0.45 m high step. if jacob’s mass is 103 kg, what is his potential energy while on top of the step? givens unkowns equation substitute solve if you could fill this in i will medal and give you brainliest answer, really struggling with this and could use a hand if you don't mind : )

Acommercial passenger jet can travel up to 970 km/hr at an altitude of 30,000 feet. at this speed, how long will it take the jet to travel 1,865 kilometers? a. 2.3 hrs b. 1.9 hrs c. 1.7 hrs d. 1.5 hrs

Laboratory experiments, observational field studies, and model-building are all examples of different forms of scientific investigations.  in what way do laboratory experiments primarily differ from other forms of scientific investigations?   a.  a laboratory experiment is the only accepted form of investigation within the scientific community.  b.  studies about how things behave in nature or studies involving very large objects are best answered through laboratory experiments.  c.  laboratory experiments involve the identification and control of variables.  d.  data can only be generated through laboratory experiments, not other forms of investigation.

Which is the correct symbol for an isotope of iodine with 53 protons and 78 neutrons?