Two spaceships are traveling past earth at 90% of the speed of light in opposite directions (i. e., they are approaching each other). one turns on a searchlight, which is seen by scientists aboard the other. what speed do the scientists measure for this light (c = speed of light in a vacuum)?

If the work required to stretch a spring 3 ft beyond its natural length is 15 ft-lb, how much work is needed to stretch it 27 in. beyond its natural length?

Choose a realistic problem for which these are the correct freebody diagrams. be sure that the answer that the problem requests is consistent with the diagrams shown. choose a realistic problem for which these are the correct freebody diagrams. be sure that the answer that the problem requests is consistent with the diagrams shown. a 1.0 kg block is placed on top of a 2.0 kg block. a horizontal rope pulls the 2.0 kg block across a frictionless floor with a force of 21.0 n. the coefficient between the two blocks is 0.75. does the 1.0 kg block on top slide?

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?