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BlackZzzverrR [31]
3 years ago
13

A 2.35-kg rock is released from rest at a height of 21.4 m. Ignore air resistance and determine (a) the kinetic energy at 21.4 m

, (b) the gravitational potential energy at 21.4 m, (c) the total mechanical energy at 21.4 m, (d) the kinetic energy at 0 m, (e) the gravitational potential energy at 0 m, and (f) the total mechanical energy at 0 m.
Physics
1 answer:
kvasek [131]3 years ago
6 0

Explanation:

Given that,

The mass of rock, m = 2.35-kg

It was released from rest at a height of 21.4 m.

(a) The kinetic energy is given by : E_k=\dfrac{1}{2}mv^2

As the rock was at rest initially, it means, its kinetic energy is equal to 0.

(b) The gravitational potential energy is given by : E_p=mgh

It can be calculated as :

E_p=2.35\times 9.8\times 21.4\\\\E_p=492.84\ J

(c) The mechanical energy is equal to the sum of kinetic and potential energy such that,

M = 0 J + 492.84 J

M = 492.84 J

Hence, this is the required solution.

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What frequency is received by a stationary mouse just before being dispatched by a hawk flying at it at 24.7 m/s and emitting a
Montano1993 [528]

Answer:

   f' = 3665.51 Hz

Explanation:

given,

speed of the hawk = 24.7 m/s

frequency of screech emitted by the hawk = 3400 Hz

speed of sound = 331 m/s

By Doppler's effect

f' = (\dfrac{v}{v-v_s}})f

f' is the frequency received by the mouse

v is the speed of the sound

v_s is the speed of the hawk

now,

f' = \dfrac{341}{341-24.7}}\times 3400

   f' = 1.078 x 3400

   f' = 3665.51 Hz

The frequency received by the stationary mouse is equal to 3665.51 Hz

6 0
3 years ago
What is the efficiency of a 0.60 kg basketball that, one dropped from a 2.0 m height (from basket rim) , rebounds to 1.2 m in he
Zinaida [17]
<h2>Let us find the efficiency : Ans = 0.6</h2>

Explanation:

we know :

efficiency = output/input

We also know that :

output = m x g x h

where :

m = mass of body

g = acceleration due to gravity

h = height of body from floor

Thus, output = 0.6 x 10 x 1.2 = 7.2J

Similarly ,input = 0.6 x 10 x 2 = 12J

Thus efficiency = 7.2/12 = 0.6

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When frequency division multiplexing (FDM) is used to aggregate several modulated channels together, no separation between chann
zaharov [31]

Answer:

False.

Separation between channel is required when frequency division multiplexing (FDM) is used to aggregate several modulated channels together.

Explanation:

In Frequency Division Multiplexing (FDM), the total bandwidth is divided to a set of frequency bands that do not overlap. Each of these bands is a carrier of a different signal that is generated and modulated by one of the sending devices.

The frequency bands are separated from one another by strips of unused frequencies called the guard bands, to prevent overlapping of signals.

The modulated signals are combined together using a multiplexer (MUX) in the sending end. The combined signal is transmitted over the communication channel, thus allowing multiple independent data streams to be transmitted simultaneously. At the receiving end, the individual signals are extracted from the combined signal by the process of demultiplexing (DEMUX).

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3 years ago
Salmon often jump waterfalls to reach their
natta225 [31]

Answer:

5.0 m/s

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v_x = u cos \theta

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d=v_x t = (ucos \theta)t

where d = 1.95 m and t is the time needed to reach the final point.

Re-arranging for t,

t=\frac{d}{v_x}=\frac{d}{u cos \theta} (1)

Along the vertical direction, the equation of motion is

y=h+u_y t -\frac{1}{2}gt^2

where:

y = 0.311 m is the final height reached by the salmon

h = 0 is the initial height

u_y = u sin \theta is the vertical component of the initial velocity of the salmon

g=9.81 m/s^2 is the acceleration of gravity

t is the time

Substituting t as found in eq.(1), we get the equation

y=(u sin \theta) \frac{d}{u cos \theta}- \frac{1}{2}g\frac{d^2}{u^2 cos^2 \theta}=d tan \theta - \frac{1}{2}g\frac{d^2}{u^2 cos^2 \theta}

and we can solve this formula for u, the initial speed of the salmon:

y=d tan \theta - \frac{1}{2}g\frac{d^2}{u^2 cos^2 \theta}\\\\u=\sqrt{\frac{gd^2}{2(dtan \theta -y)cos^2 \theta}}=\sqrt{\frac{(9.81)(1.95)^2}{2((1.95)(tan 37.7^{\circ}) -0.311)cos^2 37.7^{\circ}}}=5.0 m/s

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As a mass on a spring moves farther from the equilibrium position, how do the velocity, acceleration, and force change
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Refer to the diagram shown below.

m =  the mass of the object
x = the distance of the object from the equilibrium position at time t.
v = the velocity of the object at time t
a = the acceleration of the object at time t
A =  the amplitude ( the maximum distance) of the mass from the equilibrium
        position

The oscillatory motion of the object (without damping) is given by
x(t) = A sin(ωt)
where
ω =  the circular frequency of the motion
T =  the period of the motion so that ω = (2π)/T

The velocity and acceleration are respectively
v(t) = ωA cos(ωt)
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In the equilibrium position,
x is zero;
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At the farthest distance (A) from the equilibrium position,
x is maximum;
v is zero;
a is zero.

In the graphs shown, it is assumed (for illustrative purposes) that
A = 1 and T = 1.

6 0
3 years ago
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