Broken or bruised ribs. Introduction. Broken (fractured) or bruised ribs are usually caused by a fall or blow to the chest, or occasionally by severe coughing. They can be very painful, but will normally improve within about three to six weeks. If you think you've injured your ribs, you'll often be able to look after yourself at home.
The average speed of an object is defined as the distance traveled divided by the time elapsed. Velocity is a vector quantity, and average velocity can be defined as the displacement divided by the time. For the special case of straight line motion in the x direction, the average velocity takes the form:
Speed = Distance/Time. or. s = d/t. 1  Instantaneous Speed-The speed of an object at a given moment. 2  The car may be travelling at 50 mph at this moment, but it may slow down or speed up during the next hour. 3  Average Speed-The average speed is calculated by the distance that an object traveled over a given interval of time.r. s = d/t. 1  Instantaneous Speed-The speed of an object at a given moment. 2  The car may be travelling at 50 mph at this moment, but it may slow down or speed up during the next hour. 3  Average Speed-The average speed is calculated by the distance that an object traveled over a given interval of time.