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2 years ago

7

A girl is swinging on a rope. Does the rope supporting the swing act on the girl at the very top of her swing?

2 answers:

gladu [14]2 years ago

4 0

No, I don’t think so because is a bad thing

kondaur [170]2 years ago

3 0

Yes yes yes yes yes yes yes yes

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A mechanic pushes a 3540 kg car from rest to a speed of v, doing 4864 J of work in the process. Find the speed v. Neglect fricti

topjm [15]

Answer:

1.66 m/s

Explanation:

Work or kinetic energy = $\frac{1}{2} mv^{2}$

$4864=\frac{1}{2} (3540)v^{2}$

v = 1.66 m/s

6 0

2 years ago

The wavelength of light that has a frequency of 1.20 × 1013 s-1 is ________ m.

klio [65]

The relationship between frequency and wavelength for an electromagnetic wave is
$c=f \lambda$
where
f is the frequency
$\lambda$ is the wavelength
$c=3 \cdot 10^8 m/s$ is the speed of light.

For the light in our problem, the frequency is $f=1.20 \cdot 10^{13} s^{-1}$ , so its wavelength is (re-arranging the previous formula)
$\lambda= \frac{c}{f}= \frac{3 \cdot 10^8 m/s}{1.20 \cdot 10^{13} s^{-1}}= 2.5 \cdot 10^{-5}m$

8 0

3 years ago

A 35.4 kg girl is riding on the back of a 15.23 kg cart. the cart and the kid are both moving eastward at 4.25 m/s when she step

Grace [21]

Answer:

The final velocity of the cart is $v_c = 7.02 \ m/s$

Explanation:

From the question we are told that

The mass of the girl is $m_g = 35.4 \ kg$

The mass of the cart is $m_c = 15.23 \ kg$

The speed of the cart and kid(girl) is $v = 4.25 \ m/s$

The final velocity of the girl is $v_g = 3.06 \ m/s$

Let assume that velocity eastward is positive and velocity westward is negative (Note that if we assume vise versa it wouldn't affect the answer )

The total momentum of the system before she steps off the back of the cart

is mathematically evaluated as

$p__{T1}} = (m_g + m_c) * v$

substituting values

$p__{T1}} = (35.4 + 15.23) * 4.25$

$p__{T1}} =215.17 \ kg m /s$

The total momentum after she steps off the back of the cart is mathematically evaluated as

$p__{T2}} = (m_g * v_g ) +( m_c * v_c )$

Where $v_c$ is the final velocity of the cart

substituting values

$p__{T2}} = (35.4 * 3.06 ) +( 15.23 * v_c )$

$p__{T2}} = 108. 324 + 15.23 v_c$

Now according to the law of conservation of momentum

$p__{T1}} =p__{T2}}$

So

$215.17 \ kg m /s = 108. 324 + 15.23 v_c$

=> $v_c = 7.02 \ m/s$

Since the value is positive it implies that the cart moved eastward

7 0

3 years ago

A cadillac escalade has a mass of 2 569.6 kg, if it accelerate at 4.65m/s2 what is the net force of the car

anygoal [31]

Force is equal to mass multiplied by acceleration, therefore
F=ma
m=2569.6 kg
a=4.65m/s^2
therefore F=2569.6*4.65=11948.6 (correct to 1 d.p.)

3 0

3 years ago

A 20,000 kg railroad car is traveling at 5 m/s when it collides and couples with a second, identical car at rest. What is the re

PilotLPTM [1.2K]

Ok I don’t know the answer I’m in 5th grade but 2431 is wrong

7 0

2 years ago