Average speed = total distance / total time
total distance = 40 + 20 = 60km
total time taken = 10 + 5 = 15 minutes
Average speed = 60/15 = 4km/min
If an equation is dimensionally correct, it does not mean that the equation must be true. On the other hand, when the equation is dimensionally correct, the equation cannot be true. Dimensional analysis is a technique used to check whether a relationship is correct
Answer;
The above statement is true.
-A photograph is taken by letting light fall on a light-sensitive medium, which then records the image onto that medium.
Explanation;
-A photograph is created when light is allowed to fall on a light-sensitive medium. The pattern of light creates an image that is recorded by the photographic device. How light or dark a photograph is depends on how much light was allowed to fall on the light-sensitive medium.
-A camera is a light-tight box that contains a light-sensitive material or device and a way of letting in a desired amount of light at particular times to create an image on the light-sensitive material.