Acar is traveling south at a speed of 69 miles per hour and then begins traveling west but continues traveling at the same speed. which of the following has changed?
a. velocity
b. gravity
c. mass
d. speed

Apulley system lifts a 500-ib block 1.0 foot with an effort of only 50 ib. if the 50 ib moves 30 feet, calculate the efficiency of the pulley system. a. 30% b. 33% c. 70% d. 67%

In a stagnant pool of water, a crayfish may spend much of its time lying with one side of its carapace near the surface of the water. in this position, it will move the walking legs on that side in a rhythmic back-and-forth motion. explain the likely function of this behavior.

Diamond will scratch quartz. true or false