1. Question A lift has a object of mass 5kg inside. Find the reaction force of the lift upon the object, and the object's relative weight when: The lift is descending with an acceleration of 3m/s The lift is descending with constant speed The lift is decelerating at a rate if 3m/s (while descending) 2. My attempts and reasoning I am confused about this question. I understand that on earth the acceleration due to gravity is 9.8m/s/s, and the gravitational field is 9.8n/kg. So when the lift is at constant speed, acceleration is 0, but their is still an acceleration due to gravity (otherwise the object would lift off floor), so i assume weight & reaction = (9.8 * 5)= 49N When the lift is descending at 3m/s/s, does this mean total acceleration is 9.8 + 3 = 12.8m/s, so weight and reaction both equal 12.8*5= 64N? When the lift is retarding at 3m/s/s, total acceleration= 9.8-3= 6.8N, therefore weight and reaction both = 6.8 * 5= 34N. I have no idea if my logic is right, close, or no where near, since this is what my buddy is doing, I havent done it yet, because we are in different classes. are my answers right, if not, why? PS- does anyone know a good website to help explain physics concepts at a-level/K10-12, undergrad level?