Mr. Roberts drives his car away from his house at a constant speed. Which of the following represents
speed?

Speed is represented by distance divided by time. Graphically, constant speed is represented by a horizontal line on a speed-time graph.

Explanation

In a very literal sense speed is considered to be scalar quantity and denotes how fast or quick objects move. Therefore, speed is considered to be the velocity or swiftness of an object to cover a certain amount of distance.There three types of speed high speed, average speed, and zero speed. Any object which moves at very high speed or moves very fast and quickly and subsequently can cover the considerable distance is called high-speed object. On the other hand, the average speed of an object is defined as the total distance covered divided by the time taken to cover that distance. Again when the object doesn't cover any distance at a given time or any object which has got no movement in it is called zero speed object.Constant speed objects are those objects which move at a constant speed. Constant speed here refers to mean objects which move at the same speed without increasing or decreasing.If we try to represent constant speed on the diagram or through graph it can be done by drawing a horizontal line on the speed-time- graph. Here Mr. Robert drives his car at a constant speed means that he was driving his car without increasing or decreasing the speed or at the same speed.It has the same increase in distance in the given time. Time increases at the right and distance increase constantly with time.