Zach, whose mass is 90 kg , is in an elevator descending at 12 m/s . the elevator takes 3.0 s to brake to a stop at the first floor. part a what is zach's apparent weight before the elevator starts braking?

apparent weight will be 1242.9 N

Explanation:

As we know that elevator is moving downwards with speed 12 m/s

now it will comes to stop after t = 3 s

so the acceleration of the elevator is opposite to the direction of its motion

It is given as

now the normal force on the person who is on the elevator is given as

so apparent weight will be 1242.9 N

thermal energy is the answer

pythagoras' theorem

square root (-5^2+9^2)

square root (25+81)

square root (106)

angle is tan^-1(9/5)

neg x, pos y