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3 years ago

3. A sprinter leaves the starting blocks with an acceleration of 4.5 m/s2. What is the

Physics

1 answer:

UkoKoshka [18]3 years ago

5 0

Hi there! :)

$\large\boxed{v_{f} = 18 m/s}$

Use the following kinematic equation to solve for the final velocity:

$v_{f} = v_{i} + at$

In this instance, the runner started from rest, so the initial velocity is 0 m/s. We can rewrite the equation as:

$v_{f} = at$

Plug in the given acceleration and time:

$v_{f} = 4.5 * 4 = 18 m/s$

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Tea in a kettle cools slowly but cools faster in cup

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Explanation:

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Li is riding her bicycle at 8.0 m/s. She slows down to 4.0 m/s. Her change in velocity is m/s. If Li takes 2 seconds to make thi

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You will have to use this formula:
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Final Velocity (V) = 4m/s
Initial Velocity (Vo) = 8m/s
Acceleration (a) = ? m/s^2
Time (t) = 2 secs

Then:

-> 4 = 8 + a x 2
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Ps: It's value is negative because the she was in retrograde motion.

Answer: Her acceleration is -2 m/s^2.

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4 years ago

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A hammer taps on the end of a 4.10-m-long metal bar at room temperature. A microphone at the other end of the bar picks up two p

xz_007 [3.2K]

Answer:

Speed of sound inside metal is ≅ 8200 $\frac{m}{s}$

Explanation:

Given :

Length of metal bar $x = 4.10$ m

From general velocity equation,

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Where $v =$ speed of sound in air = 343 $\frac{m}{s}$

For finding time from above equation,

$t = \frac{x}{v}$

$t = \frac{4}{343}$

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Since pulses are separated by $t_{o} =$ $11.1 \times 10^{-3} = 0.0111$ sec

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The speed of the car at the bottom of the hill is obtained as, $v = \sqrt{2gh}$

According the principle of conservation of energy, the total potential energy of the car will be converted to maximum kinetic energy when the car is at the bottom of the hill.

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where;

v is the speed of the car at the bottom of the hill
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Thus, the speed of the car at the bottom of the hill is obtained as, $v = \sqrt{2gh}$

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