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ICE Princess25 [194]
3 years ago
8

The auto in the sketch moves forward as the brakes are applied. A bystander says that during the interval of braking, the auto's

velocity and acceleration are in opposite directions. Do you agree or disagree?
Physics
1 answer:
Ivan3 years ago
3 0

Answer:

The statement is true: velocity and acceleration have opposite directions in the interval of braking.

Explanation:

Let's say we have a velocity v>0.

The acceleration a is the rate of change of the velocity v. This means that if v is <em>increasing during</em> time, then a must be positive. But if v is <em>decreasing over</em> time, then a will be negative (even though the velocity is positive).

Mathematically:

a=\frac{dv}{dt}

v decreases ⇒\frac{dv}{dt}

⇒a.

Example:

v(t)=e^{-t}>0 \\\\\frac{dv}{dt}=-te^{-t}

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Answer:

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