Considering that the book is moving with constant speed, the force applied by Anna must be the same that the friction force:
If we clear the previous equation:
Answer:
According to your question although I think an object undergoing uniform circular motion is moving with a constant speed. Nevertheless, it is accelerating due to its change in direction. The direction of the acceleration is inwards,therefore a force perpendicular to an objects velocity change the direction of the velocity but not its magnitude.
Twin type has less to do with what twins look like and more to do with how they formed.
Identical, or monozygotic, twins form when a single fertilized egg splits and develop as two babies in the uterus. Identical twins originate from the same combination of cells and have the same genetic origin. They are ALWAYS the same sex, two girls/two boys. They may look very similar and it may be difficult to tell them apart.
Fraternal, or dizygotic, twins are two individuals from the same pregnancy who from TWO SEPARATE eggs fertilized by TWO SEPARATE SPERM. The genetic similarity between fraternal twins is the same as any two siblings, about 50 percent. They can be boys, girls, or one of each.
It is know as smoke because if you cook food smoke will go up in the air and that makes vapor and also water from the ground it suck up
