Technician a says that the engine drives the u-joint at a constant speed, but the output speed of the u-joint changes based on the angle. technician b says that smaller u-joint angles create greater changes in speed. which technician is correct?

What is the final velocity of the initial velocity of 25 and -50?

You have two photos of a person walking. one shows the person at the corner of third and main streets, the other shows the person at the corner of tenth and main streets. there are lampposts at every corner in this town, and the first picture shows it to be 10: 32: 00 exactly. the second picture shows it to be 10: 49: 30. you know three facts: (1) all of the clocks are synchronized; (2) there are exactly 12 equal-sized blocks per kilometer in this town; and (3) the streets that cross main in this area are numbered consecutively, with no interruptions. what is the person’s average speed in kilometers per hour?

When doing scientific research ,the sources used should be ?