1. A girl lifts her 19-kg knapsack a vertical distance of 0.85 m and then she carries it 1310 m across the park to the water fountain. The value of the work done by the girl is __________ J.

2. The line in the graph above illustrates an object undergoing__________ acceleration.

3. A worker slides a block of wood along a surface. The work output is determined to be 4.15 x 103 J and the worker's efficiency is 28%. The work input that would be required to produce the same work output is __________ . Record your answer to the nearest whole number of Joules.