Abus travels a distance of 120 km with a speed of 40km per hour and returns with a speed of 30km per hour calculate the average speed for the entire journey

35 km/hr

Explanation:

Average speed = (total of the speed)/(the sets of speeds given)

Direction does not matter in this instance since speed is only magnitude,

Average speed = (30 + 40)/2

Average speed = 70 ÷ 2

= 35 km/hr

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me

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.