1) A truck driver applies the brakes to bring his vehicle to a stop. The distance s, in meters, traveled "t" seconds after the moment when the brakes are applied is given by s (t) = 40t - 4t ^ 2. Determine how long it will take for the truck to stop.

1) A truck driver applies the brakes to bring his vehicle to a stop. The distance s, in meters,

traveled "t" seconds after the moment when the brakes are applied is given by

s (t) = 40t - 4t ^ 2. Determine how long it will take for the truck to stop.

2) We must make a cardboard box without a lid, from a rectangular piece

48 cm by 36 cm, by cutting a square at each of the corners and folding the walls towards the

top (as shown). The volume of the box obtained depends on the size of the

cut squares, and is given by the function

V (x) = x (48-2x) (36-2x), where x represents

the dimension, in centimeters, of the cut squares and V represents the volume, in cm3, of the

box. Determine the size of the squares that will maximize the volume.

3) An object is suspended by two 25 cm pieces of string. These are attached to a horizontal rod at points A and B. If these points slowly move away horizontally at 2 cm per minute in opposite directions, determine how fast the object is approaching horizontal 10 minutes after the start of the movement.