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3 years ago

how height does a 2.5 Kg object rises when 255J of work done against gravity A 637.5 B 20.5 C 15m D 10.2 m

Physics

2 answers:

xz_007 [3.2K]3 years ago

8 0

Answer:

Explanation:

Work = Mass * Gravity(9.8) * Height

height=work/(mass*9.8)

height=255/(2.5*9.8)=10.4m

balu736 [363]3 years ago

7 0

Answer:

D 10.2

Explanation:

255 ÷ 2.5= 10.2 or D

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A cyclist is riding a bicycle at a speed of 22 mph on a horizontal road. The distance between the axles is 42 in., and the mass

stealth61 [152]

Answer:

The shortest distance is $S = 24.86 ft$

Explanation:

The free body diagram of this question is shown on the first uploaded image

From the question we are told that

The speed of the bicycle is $v_b = 22\ mph = 22 * \frac{5280}{3600} = 32.26 ft/s$

The distance between the axial is $d = 42 \ in$

The mass center of the cyclist and the bicycle is $m_c = 26 \ in$ behind the front axle

The mass center of the cyclist and the bicycle is $m_h = 40 \ in$ above the ground

For the bicycle not to be thrown over the

Momentum about the back wheel must be zero so

$\sum _B = 0$

=> $mg (26) = ma(40)$

=> $a = \frac{26}{40} g$

Here $g = 32.2 ft/s^2$

So $a = \frac{26}{40} (32.2)$

$a = 20.93 ft/s^2$

Apply the equation of motion to this motion we have

$v^2 = u^2 + 2as$

Where $u = 32.26 ft /s$

and $v = 0$ since the bicycle is coming to a stop

$v^2 = (32.26)^2 - 2(20.93) S$

=> $S = 24.86 ft$

5 0

3 years ago

A ball is thrown vertically upward from the top of a building 80 feet tall with an initial velocity of 64 feet per second. The d

-BARSIC- [3]

Answer:

a) $t=6.37s$

b) $t=3.3333s$

Explanation:

The knowable variables are the initial hight and initial velocity

$s_{o}=80ft$

$v_{os}=64ft/s$

The equation that describes the motion of the ball is:

$s=80+64t-16t^{2}$

If we want to know the time that takes the ball to hit the ground, we need to calculate it by doing s=0 that is the final hight.

$0=80+64t-12t^{2}$

a) Solving for t, we are going to have two answers

$t=\frac{-b±\sqrt{b^{2}-4ac } }{2a}$

a=-16

b=64

c=80

$t=-1.045 s$ or $t=6.378s$

<em><u>Since time can not be negative the answer is t=6.378s </u></em>

b) To find the time that takes the ball to pass the top of the building on its way down, we must find how much does it move too

First of all, we need to find the maximum hight and how much time does it take to reach it:

$v_{y}=v_{o}+gt$

at maximum point the velocity is 0

$0=64-32.2t$

Solving for t

$t=1.9875 s$

Now, we must know how much distance does it take to reach maximum point

$s=0+64t-16t^{2} =64(1.9875)-12(1.9875)^{2} =80ft$

So, the ball pass the top of the building on its way down at 160 ft

$160=80+64t-16t^{2}$

Solving for t

$t=2s$ or $t=3.333s$

Since the time that the ball reaches maximum point is almost t=2s that answer can not be possible, so the answer is t=3.333s for the ball to go up and down, passing the top of the building

4 0

3 years ago

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What is the average translational KE of 5 moles of gas molecules at 300 K?

aev [14]

Answer:

What is the average translational kinetic energy of molecules in an ideal gas at 37°C? The average translational energy of a molecule is given by the equipartition theorem as, E = 3kT 2 where k is the Boltzmann constant and T is the absolute temperature.

Explanation:

The average translational energy of a molecule is given by the equipartition theorem as, E = 3kT 2 where k is the Boltzmann constant and T is the absolute temperature.

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3 years ago

What is the wavelength of a 2.2 mhz ultrasound wave traveling through aluminum? assume that the speed of sound in aluminum is 51

Eva8 [605]

The frequency of a wave is equal to the linear speed divided the wavelength. so in equation form.
f = v / l
so the wavlength
l = v / f
where f is the frequency
v iss the linear speed
l is the wavelength

l = ( 5100 m/s ) / ( 2.2 Mhz ) ( 10^6 hz / 1 Mhz )
f = 0.0023 m
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3 years ago

A service elevator takes a load of garbage, mass 10.0 kg, from a floor of a skyscraper under construction, down to ground level,

kobusy [5.1K]

Answer:

The magnitude of the force the garbage exerts on the floor of the service elevator is 12 N

Explanation:

Given;

mass of the garbage, m = 10.0 kg

acceleration of the elevator, a = 1.2 m/s²

The magnitude of the force the garbage exerts on the floor of the service elevator is given by;

F = ma

F = 10 x 1.2

F = 12 N

Therefore, the magnitude of the force the garbage exerts on the floor of the service elevator is 12 N

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4 years ago

how height does a 2.5 Kg object rises when 255J of work done against gravity A 637.5 B 20.5 C 15m D 10.2 m​

how height does a 2.5 Kg object rises when 255J of work done against gravity A 637.5 B 20.5 C 15m D 10.2 m