A person who has a mass of 55 kg is standing in an elevator which is accelerating downward. Acceleration due to gravity is 10 m/s2. a) At what rate (in m/s2) must the elevator accelerate for the person to feel weightless

10 m/s²

Explanation:

The reaction on a person in an elevator that is descending  is given as

R = m(g-a) Equation 1

Where R = apparent weight of the person inside the elevator, g = acceleration due to gravity, m = mass of the person, a = acceleration of the elevator.

make a the subject of the equation

a = g-(R/m) Equation 2

Note: For weightlessness, R = 0 N.

Given: g = 10 m/s², R = 0 N (weightlessness). m = 55 kg

Substitute into equation 2

a = 10-(0/55)

a = 10-0

a = 10 m/s²

it would be kevlar ^^

b.a device that inputs heat into a cool object