Hello! Yes I know this is a lot but let me explain. this is one question I promise. so the text at the top is the problem. I attempted it by myself. I believe I got A correct, so reassurance on that would be great. but when it comes to B and C, I don't know where to put the numbers as a plug in. please help me.

A400-lb object is released from rest 500-ft above the ground and falls under the influence of gravity. assume the force in pounds due to air resistance is  where  is the velocity of the object in ft/sec, determine the equation of motion of the object. when will the object hit the ground and what is its velocity at the impact

What must be the same of two resistors that are connceted in parallel

An oil refinery produces oil at a variable rate given by the following equation, where t is measured in days and q is measure in barrels. upper q prime left parenthesis t right start 3 by 2 matrix 1st row 1st column 600 2nd column if 0 less than or equals t less than 30 2nd row 1st column 2500 minus 50 t 2nd column if 30 less than or equals t less than 40 3rd row 1st column 400 2nd column if t greater than or equals 40 endmatrix a. how many barrels are produced in the first 35 days? b. how many barrels are produced in the first 50 days? c. without using calculus, determine the number of barrels produced over the interval [70,90].