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3 years ago

8

Which has more kinetic energy, a 40 kg cheetah running at 25 m/s or a 4,000 kg elephant moving at 2 m/s? How much more energy do

es it have?

1 answer:

denis23 [38]3 years ago

8 0

Answer:

1st case; mass=40 kg

v=25m/s

K.E.=1/2[40][25]^2=12,500 J

2nd case; mass=4,000 kg

v=2 m/s

K.E.=1/2[4000][2]^2=8000J

in case 1 Kinetic energy is greater.

Explanation:

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The distance between two consecutive nodesof a standing wave is 20.9cm.Thehandgen-erating the pulses moves up and down throughac

irina1246 [14]

Answer:

Velocity, v = 0.239 m/s

Explanation:

Given that,

The distance between two consecutive nodes of a standing wave is 20.9 cm = 0.209 m

The hand generating the pulses moves up and down through a complete cycle 2.57 times every 4.47 s.

For a standing wave, the distance between two consecutive nodes is equal to half of the wavelength.

$\dfrac{\lambda}{2}=0.209\ m\\\\\lambda=0.418\ m$

Frequency is number of cycles per unit time.

$f=\dfrac{2.57}{4.47}\\\\f=0.574\ Hz$

Now we can find the velocity of the wave.

Velocity = frequency × wavelength

v = 0.574 × 0.418

v = 0.239 m/s

So, the velocity of the wave is 0.239 m/s.

4 0

3 years ago

Why can't seismic stations locate the foucs? Why can they only locate the epicenter?

Tasya [4]

The focus of an earthquake is internal and is harder to record than the waves of an epicenter, which are on the surface.

4 0

4 years ago

What causes interstellar dust and clouds into plants and stars

AnnZ [28]

I assume you mean planets eitherway interstellar dust and clouds have solid material and as well as minerals such as iron and over time solid chuncks start to fuse together and make a planet but with stars however it is different because a star has a little solid core surrounded by gasses (hydrogen and helium) to produce heat in a method called nuclear fusion so interstellar clouds contain gasses as well and solids as I previously said and form a star as well

this is from my understanding

5 0

4 years ago

A pulley of radius 8.0 cm is connected to a motor that rotates at a rate 7000 rad s-1 and then decelerate uniformly at a rate of

zlopas [31]

Answer:

(a) α = - 1000 rad/s²

Negative sign represents deceleration.

(b) θ = 3581 rotations

(c) L = 1800 m

(d) a = - 80 m/s²

Explanation:

(a)

using First equation of motion for angular motion:

ωf = ωi + αt

where,

ωf = Final Angular Speed = 2000 rad/s

ωi = Initial Angular Speed = 7000 rad/s

α = Angular Acceleration = ?

t = time = 5 s

Therefore,

2000 rad/s = 7000 rad/s + α(5s)

α = (2000 rad/s - 7000 rad/s)/5 s

<u>α = - 1000 rad/s²</u>

<u>Negative sign represents deceleration.</u>

(b)

Using second equation of motion:

θ = ωi t + (1/2)αt²

where,

θ = No. of Rotations = ?

Therefore,

θ = (7000 rad/s)(5 s) + (1/2)(- 1000 rad/s²)(5 s)²

θ = 35000 rad - 12500 rad

θ = (22500 rad)(1 rotation/2π rad)

<u>θ = 3581 rotations</u>

(c)

Length of String = L = (Circumference of Pulley)(θ)

L = [2π(0.08 m)][3581 rotations]

<u>L = 1800 m</u>

<u></u>

(d)

Tangential Acceleration = a = rα

a = (0.08 m)(-1000 rad/s²)

<u>a = - 80 m/s²</u>

4 0

3 years ago

Why is it important to keep the muzzle of a firearm pointed in a safe direction, even though the firearm's safety is engaged?

Gnom [1K]

The correct answer is B. The safety only prevents you from pulling the trigger, but does not stop the pin from striking the primer. For example, if you drop the firearm, the pin may hit the primer and fire the firearm. It is always responsible to keep the firearm pointed in a safe direction so that if this happens, no consequences come out of it.

6 0

3 years ago