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Ad libitum [116K]

3 years ago

11

A spacecraft that renters the earth’s atmosphere drastically slows down. The amount of kinetic energy the spacecraft has as it r

eenters the earths atmosphere

1 answer:

Andrei [34K]3 years ago

5 0

it will go down fast and burn

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A baseball pitcher loosens up his pitching arm. He tosses a 0.20-kg ball using only the rotation of his forearm, 0.28 m in lengt

gayaneshka [121]

Answer:

Moment of Inertia, I = 0.016 kgm²

Explanation:

Mass of the ball, m = 0.20 kg

Length of the pitcher's arm, l = 0.28

Radius of the circular arc, r = 0.28 m

Moment of Inertia is given by the formula:

I = mr²

I = 0.20 * 0.28²

I = 0.20 * 0.0784

I = 0.01568

I = 0.016 kgm²

5 0

4 years ago

If a melon has a a mass of 1 kg, how much does the melon weigh?

lesya [120]

Answer:

A. 10 N

Explanation:

weight of melon is 1×10=10N..........

6 0

3 years ago

A 45.0-kg girl is standing on a 168-kg plank. The plank, originally at rest, is free to slide on a frozen lake, which is a flat,

muminat

Answer:

The speed of the plank relative to the ice is:

$v_{p}=-0.33\: m/s$

Explanation:

Here we can use momentum conservation. Do not forget it is relative to the ice.

$m_{g}v_{g}+m_{p}v_{p}=0$ (1)

Where:

m(g) is the mass of the girl
m(p) is the mass of the plank
v(g) is the speed of the girl
v(p) is the speed of the plank

Now, as we have relative velocities, we have:

$v_{g/b}=v_{g}-v_{p}=1.55 \: m/s$ (2)

v(g/b) is the speed of the girl relative to the plank

Solving the system of equations (1) and (2)

$45v_{g}+168v_{p}=0$

$v_{g}-v_{p}=1.55$

$v_{p}=-0.33\: m/s$

I hope it helps you!

8 0

3 years ago

What substances help muscles move

harkovskaia [24]

Together, our bones, muscles, and joints along with tendons, ligaments, and cartilage form our musculoskeletal system and enable us to do everyday physical activities

8 0

3 years ago

Photons with wavelength 1 pm are incident on electrons. What is the frequency of the Compton-scattered photons at an angle of 60

natali 33 [55]

Answer:

f = 1.354*10^{20} Hz

Explanation:

By conservation of linear momentum, wavelength shift due to collision of photon to electron is given by following formula

$\lambda ^{'}-\lambda =\frac{h}{m_{o}c}(1-cos\theta )$

where h is plank constant = 6.626*10^{-34}

c = speed of light = 3*10^{8} m/s

scattered angle = 60 degree

m = rest mass of electron = 9*10^{-31}

$\lambda ^{'}=10^{-12} +\frac{6.626*10^{-34}}{9*10^{-31}*3*10^{8}}(1-cos60^{o} )$

$\lambda ^{'}= 2.215 pm$

we know that 1 pm = 10^{-12}m

$f = \frac{c}{\lambda ^{'}}$

$f = \frac{3*10^{8}}{2.215 *10^{-12}} = 1.354*10^{20} Hz$

f = 1.354*10^{20} Hz

4 0

3 years ago