Processes: motion and work
Solve problems of simultaneous motion and of joint work with one plan: speed · time = distance, productivity · time = output.
- Ukraine: grade 4
- Russia: grade 4
Guide
Ukrainian Grade 4 (part 2) calls problems on motion and on joint work problems on processes. A motion process has speed v, time t and distance s: v · t = s. A work process has productivity, working time and total output: productivity · time = output.
The short record is a table with rows I, II and "I and II". Two ways: first way 29 · 5 + 35 · 5; second way (29 + 35) · 5. If the bodies (workers) move (work) at the same time, their speeds (productivities) are added.
To find the speed of one body (the productivity of one worker), find the joint speed (joint productivity) and subtract the known one. To find the time of joint motion (joint work), divide the total distance (output) by the joint speed (productivity).