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grin007 [14]
3 years ago
13

A ball is dropped off a roof. The ball falls for 4 seconds. Just before the ball hits the ground what is its velocity?

Physics
1 answer:
scZoUnD [109]3 years ago
7 0

Answer:

<em>The velocity is 39.24 m/s</em>

<em></em>

Explanation:

The time of fall t = 4 seconds

The initial velocity u = 0 m/s  (since the ball is dropped, meaning it starts from rest)

Final velocity v = ?

Using

v = u + gt

where g is the acceleration due to gravity = 9.81 m/s^2

substituting, we'll have

v = 0 + (9.81 x 4)

v = <em>39.24 m/s</em>

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If a transmission line in a cold climate collects ice, the increased diameter tends to cause vortex formation in a passing wind.
AleksAgata [21]

Answer:

a) f_1=5.587Hz

b) f_{n+1}-f_n=5.587Hz

Explanation:

The frequency of the n^{th} harmonic of a vibrating string of length <em>L, </em>linear density \mu under a tension <em>T</em> is given by the formula:

f_n=\frac{n}{2L} \sqrt{\frac{T}{\mu}

a) So for the <em>fundamental mode</em> (n=1) we have, substituting our values:

f_1=\frac{1}{2(347m)} \sqrt{\frac{65.4\times10^6N}{4.35kg/m}}=5.587Hz

b) The <em>frequency difference</em> between successive modes is the fundamental frequency, since:

f_{n+1}-f_n=\frac{n+1}{2L} \sqrt{\frac{T}{\mu}}-\frac{n}{2L} \sqrt{\frac{T}{\mu}}=(n+1-n)\frac{1}{2L} \sqrt{\frac{T}{\mu}}=\frac{n}{2L} \sqrt{\frac{T}{\mu}}=f_1=5.587Hz

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2 years ago
8. A driver starts his parked car and within 12 hours reaches a speed of 75km/h, as he travels
erastovalidia [21]

Answer:

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2 years ago
During a free fall Swati was accelerating at -9.8m/s2. After 120 seconds how far did she travel? Use the formula =1/2 *
marta [7]
Distance fallen = 1/2 ( V initial + V final ) *t
We know
a = -9.8 m/s2
t=120s

To find distance fallen, we need to find V final
Use the equation
V final = V initial + a*t
Substitute known values
V final = 0 + (-9.8)(120)
V final = -1176 m/s

Then plug known values to distance fallen equation
Distance fallen = 1/2 ( 0 + 1176 )(120)
= 1/2(1776)(120)
=106,560 m

This way plugging into distance equation is actually the long way. A faster way is to plug the values into
Distance fallen = V initial * t + 1/2(a*t)
We won't need to find V final using another equation.

But anyways, good luck!



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Answer:

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