A 1.6kg mass is suspended from a string in a stationary elevator. The spring stretches 12cm. The elevator now accelerates upward, and the spring extends a further 12cm. What is the acceleration in the elevator?
A hand supports two books, ma and mb, with ma on top. The hand accelerates the books p and to the right, with a pushing force directed 64° above horizontal. Assuming the upper book does not slip, draw a free body diagram for each book.
My attempt: