1) There are two questions which are copy-pasted down below:

a) A 72 Ohm Coil of Wire Is Connected in Series with An Adjustable Resistor (rheostat) Whose Resistance Can Be Varied from 0 to 88 Ohms. if The Line Potential of Wire Is 115 Volts, What Is the Rheostat Resistance when Power Taken by The Coil Is 90 Watts?

b)A mass m is moving (on planet Earth) on a horizontal surface with a velocity ux = 30 ms^-1. The mass reaches a ledge with a sharp vertical drop of 100 m above the ocean below (similar to a cliff edge). The mass moves off the ledge, travels through the air and lands in the ocean.

a) Calculate the furthest horizontal distance reached by the mass.

b) Explain, using words, why we are justified in using the uniform acceleration equations when considering the motion of this mass. State a scenario in which this approximation is no longer valid.