Aconvex mirror can form question 5 options: both virtual and real images. only real images. only virtual images. none of the above

c because the action was the roller coaster reaches bottom of hill (action) reaction would be blood tends to drain away from head

hope this !

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