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3 years ago

10

A rock weighing 98 newtons is pushed off the edge of a bridge 50 meters above the ground. What was the kinetic energy of the roc

k at the midway point of its fall?

1 answer:

Ahat [919]3 years ago

3 0

2,450 Joules, kinetic energy is 1/2 mass x velocity squared.

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A long ramp made of cast iron is sloped at a constant angle θ = 52.0∘ above the horizontal. Small blocks, each with mass 0.42 kg

dezoksy [38]

Answer:

For cast iron we have

$h = 0.92 m$

For copper

$h = 1.05 m$

For Lead

$h = 1.23 m$

For Zinc

$h = 2.43 m$

Explanation:

As we know that final speed of the block is calculated by work energy theorem

$W_f + W_g = \frac{1}{2}mv^2$

now we have

$-\mu_k mg cos\theta(\frac{h}{sin\theta}) + mgh = \frac{1}{2}mv^2$

now we have

$v^2 = 2gh - 2\mu_k g h cot\theta$

$v = \sqrt{2gh(1 - \mu_k cot\theta)}$

For cast iron we have

$4 = \sqrt{2(9.81)(h)(1 - 0.15cot52)}$

$h = 0.92 m$

For copper

$4 = \sqrt{2(9.81)(h)(1 - 0.29cot52)}$

$h = 1.05 m$

For Lead

$4 = \sqrt{2(9.81)(h)(1 - 0.43cot52)}$

$h = 1.23 m$

For Zinc

$4 = \sqrt{2(9.81)(h)(1 - 0.85cot52)}$

$h = 2.43 m$

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3 years ago

The diameter of an atom is 1.1×10−10m and the diameter of its nucleus is 1.0×10−14m. Part A What percent of the atom's volume is

77julia77 [94]

To solve this problem we will use the basic concept given by the Volume of a sphere with which the atom approaches. The fraction in percentage terms would be given by the division of the total volume of the nucleus by that of the volume of the atom, that is,

$\% Percent = \frac{V_{nucleus}}{V_{atom}}*100$

$\% Percent = \frac{4/3 \pi (d_{nucleus}/2)^3}{4/3 \pi (d_{atom}/2)^3}*100$

$\% Percent = \frac{(d_{nucleus}/2)^3}{ (d_{atom}/2)^3}*100$

$\% Percent =\frac{(1.0*10^{-14}/2)^3}{ (1.1*10^{-10}/2)^3}*100$

$\% Percent = 7.51*10^{-13}*100$

$\% Percent = 7.51*10^{-11}\%$

Therefore the percent of the atom's volume is occupied by mass is $7.51*10^{-11}\%$

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2 years ago

How might what is happening in this image affect the nervous system?

Yuri [45]

There is no image!?...was there meant to be something attached?

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3 years ago

Older televisions display a picture using a device called a cathode ray tube, where electrons are emitted at high speed and coll

Len [333]

Answer:

Explanation:

initial velocity v = 2.1 x 10⁷ m/s

acceleration a = 5.1 x 10¹⁵ m /s²

horizontal distance covered = 5.5 x 10⁻² m

time taken to cover horizontal distance = 5.5 x 10⁻² / 2.1 x 10⁷

= 2.62 x 10⁻⁹ s .

b )

vertical distance travelled due to vertical acceleration

= 1/2 a t²

= .5 x 5.1 x 10¹⁵ x (2.62 x 10⁻⁹)²

= 17.5 x 10⁻³ m

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3 years ago

If you weigh 120 pounds on earth what is your weight on the moon

rusak2 [61]

Moons gravity is about 1/6 as powerful as it is on Earth, so about 20 pounds.

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