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Shkiper50 [21]
3 years ago
8

What is the speed of a 500 kg elevator that has 4000 J of energy ?

Physics
1 answer:
malfutka [58]3 years ago
8 0
Energy =sxm
S =4000/500
=Answer
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If a car moves with a uniform speed of 2m/s in a circle of radius 0.4m, what is its angular speed?
REY [17]

Answer:

The car's angular speed is \frac{rad}{s}.

Explanation:

Angular velocity is usually measured with \frac{radians}{sec}, so I'm going to use that to answer your question.

The relationship between tangential velocity and angular velocity (ω)  is given by:

V = \omega R

Using the values from the question, we get:

2 \frac{m}{s} = \omega (0.4m)

\omega = 5 \frac{rad}{s}

Therefore, the car's angular speed is 5 \frac{rad}{s}.

Hope this helped!

3 0
3 years ago
A thin rod of length 0.75 m and mass 0.42 kg is suspended
MrRissso [65]

Answer:

a)  K = 0.63 J, b)  h = 0.153 m

Explanation:

a) In this exercise we have a physical pendulum since the rod is a material object, the angular velocity is

         w² = \frac{m g d}{I}

where d is the distance from the pivot point to the center of mass and I is the moment of inertia.

The rod is a homogeneous body so its center of mass is at the geometric center of the rod.

              d = L / 2

the moment of inertia of the rod is the moment of a rod supported at one end

              I = ⅓ m L²

we substitute

            w = \sqrt{\frac{mgL}{2}  \ \frac{1}{\frac{1}{3} mL^2} }

            w = \sqrt{\frac{3}{2}  \ \frac{g}{L} }

            w = \sqrt{ \frac{3}{2} \ \frac{9.8}{0.75}  }

            w = 4.427 rad / s

an oscillatory system is described by the expression

              θ = θ₀ cos (wt + Φ)

the angular velocity is

             w = dθ /dt

             w = - θ₀ w sin (wt + Ф)

In this exercise, the kinetic energy is requested in the lowest position, in this position the energy is maximum. For this expression to be maximum, the sine function must be equal to ±1

In the exercise it is indicated that at the lowest point the angular velocity is

           w = 4.0 rad / s

the kinetic energy is

           K = ½ I w²

           K = ½ (⅓ m L²) w²

           K = 1/6 m L² w²

           K = 1/6 0.42 0.75² 4.0²

           K = 0.63 J

b) for this part let's use conservation of energy

starting point. Lowest point

             Em₀ = K = ½ I w²

final point. Highest point

             Em_f = U = m g h

energy is conserved

             Em₀ = Em_f

             ½ I w² = m g h

             ½ (⅓ m L²) w² = m g h

             h = 1/6 L² w² / g

             h = 1/6 0.75² 4.0² / 9.8

             h = 0.153 m

5 0
2 years ago
The slope of the line on a speed-time graph tells the speed , true or false ?
KengaRu [80]
True I hope this helps you out 
8 0
3 years ago
Read 2 more answers
Need physics help<br> ASAP please!
Effectus [21]

Answer:

D

Explanation:

7 0
3 years ago
Damping is negligible for a 0.135-kg object hanging from a light, 6.30-N/m spring. A sinusoidal force with an amplitude of 1.70
IceJOKER [234]

Answer:

0.72 Hz minimum frequency

Explanation:

When the damping is negligible,Amplitude is given as

A = (F/m)/[\sqrt{(\omega ^{^{2}}-\omega _{o}^{2}})^2

here \omega _{o}^{2}= k/m = (6.30)/(0.135) = 46.67 N/m kg

F / mA = 1.70/(0.135)(0.480) = 26.2 N/m kg

From the above equation , rearranging for ω,

\omega ^{2}= \omega _{o}^{2}\pm F/m

⇒ ω² =46.67 ± 26.2 = 72.87 or 20.47

⇒ ω = 8.53 or 4.52 rad/s

Frequency = f

ω=2 π f

⇒ f = ω / 2π =  8.53 /6.28  or 4.52 / 6.28 = 1.36 Hz or 0.72 Hz

The lower frequency is 0.72 Hz and higher is 1.36 Hz

8 0
3 years ago
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