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almond37 [142]
3 years ago
12

A truck is moving with a certain uniform velocity. It is accelerated uniformly by 0.75 m/s^2. After 20 seconds , the velocity be

comes 72km/h.Find the initial velocity
Physics
1 answer:
scoundrel [369]3 years ago
5 0

Answer:

Vi = 5 m/s

Explanation:

let (a) acceleration = 0.75 m/s²

(t) time = 20 seconds

Vf = final velocity = 72 km/hr  (convert to m/s to units consistency = 20 m/s)

find Initial velocity (Vi)

       Vf - Vi

a =  -----------

             t

Vi = Vf - (a * t)  = 20 - (0.75 * 20)

Vi = 5 m/s

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A resistor is connected in series with an AC source that provides a sinusoidal voltage of v of t is equal to V times cosine of b
nekit [7.7K]
<h2>Answer:</h2>

In circuits, the average power is defined as the average of the instantaneous power  over one period. The instantaneous power can be found as:

p(t)=v(t)i(t)

So the average power is:

P=\frac{1}{T}\intop_{0}^{T}p(t)dt

But:

v(t)=v_{m}cos(\omega t) \\ \\ i(t)=i_{m}cos(\omega t)

So:

P=\frac{1}{T}\intop_{0}^{T}v_{m}cos(\omega t)i_{m}cos(\omega t)dt \\ \\ P=\frac{v_{m}i_{m}}{T}\intop_{0}^{T}cos^{2}(\omega t)dt \\ \\ But: cos^{2}(\omega t)=\frac{1+cos(2\omega t)}{2}

P=\frac{v_{m}i_{m}}{T}\intop_{0}^{T}(\frac{1+cos(2\omega t)}{2} )dt \\\\P=\frac{v_{m}i_{m}}{T}\intop_{0}^{T}[\frac{1}{2}+\frac{cos(2\omega t)}{2}]dt \\\\P=\frac{v_{m}i_{m}}{T}[\frac{1}{2}(t)\right|_0^T +\frac{sin(2\omega t)}{4\omega} \right|_0^T] \\ \\ P=\frac{v_{m}i_{m}}{2T}[(t)\right|_0^T +\frac{sin(2\omega t)}{2\omega} \right|_0^T] \\ \\ P=\frac{v_{m}i_{m}}{2}

In terms of RMS values:

V_{RMS}=V=\frac{v_{m}}{\sqrt{2}} \\ \\ I_{RMS}=I=\frac{i_{m}}{\sqrt{2}} \\ \\ Then: \\ \\ P=VI

7 0
3 years ago
A wave travels down the length of a 25-meter rope in 5.0 seconds. The speed of the wave is _____.
Alborosie
Speed
= (distance covered) / (time to cover the distance)

= (25 m) / (5.0 sec) = 5.0 m/s .
4 0
3 years ago
Read 2 more answers
26. A baseball traveling 38 m/s is caught by the catcher. The catcher takes 0.1 seconds to stop the ball. What is the accelerati
Furkat [3]

Answer:

The ball has an acceleration of -380 m/s², this means the ball slows down

An acceleration of -380 m/s² is the equivalent of 38.736 g's

Explanation:

Step 1: Data given

Velocity of the baseball at time t=0 = 38 m/s

At time t, the ball stops. This means v = 0

time before stops = 0.1s

Step 2: Calculate the acceleration

v= v0+at

with v= the velocity of the ball at time t = 0. v= 0

with v0 = the velocity of the ball at time t=0. v0 = 38 m/s

with a= the acceleration in m/s²

with t = time in seconds

0 = 38 + a*0.1

a = -380 m/s²

The ball has an acceleration of -380 m/s², this means the ball slows down

An acceleration of -380 m/s² is the equivalent of 38.736 g's

5 0
3 years ago
4. If the velocity of the particles is high, they will collide with each other with less force.
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Answer:

7657

Explanation:

3 0
3 years ago
An oven mitt is made of a material that is a poor thermal conductor.
ddd [48]

Answer:

D

Explanation:

5 0
3 years ago
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