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kirill [66]
4 years ago
12

An absent-minded Penn State professor drives from State College to Tyrone, 20 miles away, at 60 mph (miles per hour), before rea

lizing that he forgot his wallet. He immediately returns to State College at 60 mph, picks up his wallet and drives back to Tyrone at 60 mph. Assuming all the travel was done more or less on a straight line and neglecting the time taken to turn around or collect the professor's wallet, what is the magnitude of the professor's average velocity for the entire trip?
Physics
1 answer:
BaLLatris [955]4 years ago
8 0

Answer:20 mph

Explanation:

Given

distance between college to Tyrone=20 miles

Given professor drives with a velocity of 60 mph

he returns to college after reaching tyrone and then again drive to tyrone.

so his net displacement is 20 miles

time taken to cover 20 miles is \frac{1}{3} hr

average velocity=\frac{Displacement}{Time\ taken}

V_{avg}=\frac{20}{\frac{1}{3}+\frac{1}{3}+\frac{1}{3}}

V_{avg}=\frac{20}{1}=20 mph

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Darya [45]

To answer the two questions, we need to know two important equations involving centripetal movement:

v = ωr (ω represents angular velocity <u>in radians</u>)

a = \frac{v^{2}}{r}

Let's apply the first equation to question a:

v = ωr

v = ((1800*2π) / 60) * 0.26

Wait. 2π? 0.26? 60? Let's break down why these numbers are written differently. In order to use the equation v = ωr, it is important that the units of ω is in radians. Since one revolution is equivalent to 2π radians, we can easily do the conversion from revolutions to radians by multiplying it by 2π. As for 0.26, note that the question asks for the units to be m/s. Since we need meters, we simply convert 26 cm, our radius, into meters. The revolutions is also given in revs/min, and we need to convert it into revs/sec so that we can get our final units correct. As a result, we divide the rate by 60 to convert minutes into seconds.

Back to the equation:

v = ((1800*2π)/60) * 0.26

v = (1800*2(3.14)/60) * 0.26

v = (11304/60) * 0.26

v = 188.4 * 0.26

v = 48.984

v = 49 (m/s)

Now that we know the linear velocity, we can find the centripetal acceleration:

a = \frac{v^{2}}{r}

a = \frac{49^{2}}{0.26}

a = 9234.6 (m/s^{2})

Wow! That's fast!

<u>We now have our answers for a and b:</u>

a. 49 (m/s)

b. 9.2 * 10^{3} (m/s^{2})

If you have any questions on how I got to these answers, just ask!

- breezyツ

5 0
3 years ago
At a certain time a particle had a speed of 48 m/s in the positive x direction, and 4.5 s later its speed was 92 m/s in the oppo
larisa86 [58]

Answer:

-31.1 m/s^2

Explanation:

The acceleration of an object is the rate of change of velocity of the object.

Mathematically, it is calculated as:

a=\frac{v-u}{t}

where

u is the initial velocity

v is the final velocity

t is the time taken for the velocity to change from u to v

Acceleration is a vector, so it is important to also take into account the direction of the velocity.

For the particle in this problem, we have:

u = +48 m/s is the initial velocity (positive direction)

v = -92 m/s is the final velocity (negative direction)

t = 4.5 s is the time interval

Therefore, the average acceleration is

a=\frac{v-u}{t}=\frac{-92-(+48)}{4.5}=-31.1 m/s^2

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3 years ago
Anika asks Eva to roll a basketball and then a bowling ball to her. Which requires more force to roll, and why?
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Answer:

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Explanation:

Acceleration is given by

a=\frac{\Delta v}{\Delta t}

where

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To find the acceleration at 1 second, we can take the data at t = 1 s and t = 2. We find:

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7nadin3 [17]

Answer: Spina bifida

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