An astronaut has left the International Space Station to test a new space scooter. Her partner measures the following velocity changes, each taking place in a time interval 11.3 s . What are the average acceleration in each interval?

1.) At the beginning of the interval the astronaut is moving toward the right along the x-axis at 15.0 m/s, and at the end of the interval she is moving toward the right at 5.30 m/s.
a = ___________-??
2.) At the beginning she is moving toward the left at 5.30 m/s. and at the end she is moving toward the left at 15.0 m/s.
a =_________ ??
3.) At the beginning she is moving toward the right at 15.0 m/s, and at the end she is moving toward the left at 15.0 m/s.
a = _________??