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# quick help on a question?

Q: A car that has a speed of 15mph accelerates for 7seconds at a rate of 2mph/s. What is the velocity of th object at the end of the acceleration?

AND

Sarah is driving down the highway at 50mph when a deer jumps in front of her car. Sarah accelerates for 2 seconds at -20mph/s before striking the deer. What is her speed when she hits the deer?

thank you so much for you help.

### 2 Answers

- wjllopeLv 71 decade agoFavorite Answer
a= 2mph/sec (strange unit but it's all we need here so no problem)

v = v0 + a*t

v = 15mph + (2 mph/s)*7s = 29mph

for the second part, it's just the same equation with different inputs..

v = v0 + a*t

v = 50mph + (-20 mph/s)*2sec

v = 10mph

EDIT: by the way, make sure to *always* quote results with their units. some teachers mark down for failing to carry the units through and quoting the final result *with* their units.

i do.

- Anonymous1 decade ago
15 + 2(7) = 29

50 - 2(20) = 10