An engineering student was helping in the design of a new runway. His mentor told him the airplanes must reach a ground velocity of 55 m/s before they can take off. These planes are
capable of being accelerated at a rate of 2.8 m/s?.
a. How long will it take the planes to reach takeoff speed?
b. What must be the minimum length of the runway?

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.

myth. it was once thought that animals, including cats and dogs, could only see in black and white. however, scientists have proven this to be a myth. in all animals, including humans, the perception of colour is determined by the presence of cells in the eye called cone photoreceptors.