Cars a and b are racing each other along the same straight road in the following manner: car a has a head start and is a distance da beyond the starting line at t=0. the starting line is at x=0. car a travels at a constant speed va. car b starts at the starting line but has a better engine than car a, and thus car b travels at a constant speed vb, which is greater than va.

the earths atmosphere is made up of nitrogen and oxygen. solids can turn into gasses through a process called sublimation. sublimation is the transition of a substance directly from the solid to the gas phase, without passing through the intermediate liquid phase.

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when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.