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 : )

The density of a liquid could be found by using

Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 10.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.90 m/s; (b) he is then lifted at the constant speed of 4.90 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 68.0 kg rescue by the force lifting him during each stage?

Part a constants huck finn walks at a speed of 0.60 m/s across his raft (that is, he walks perpendicular to the raft's motion what is huck's velocity (speed and direction) relative to the river bank? express your answer to three significant figures and include the appropriate units. relative to the shore)