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Uniform Aceleration: Speed of Car at End of Braking Period

"A car accelerates from rest and travels for 4.98 s with a uniform acceleration of +1.50 m/s^2. The driver then applies the brakes, causing a uniform acceleration of -1.99 m/s^2. If the brakes are applied for 3.06s, how fast is the car going at the end of the braking period? And how far has the car gone?"

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Solution. By the hypothesis, the initial speed of the car is v0=0, and the uniform acceleration a1=1.5m/s^2. So, after t1=4.98s, the speed of the car V is

V=a1*t1=4.98*1.5=7.47 (m/s).

The direction of V is the same as the acceleration, say "right".
Then, the driver applies the brakes, causing a uniform acceleration of a2=-1.99m/s^. The "-" means decreasing ...

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