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3 years ago

If the kinetic energy of a particle is doubled, by what factor has its speed increased?

Physics

2 answers:

zimovet [89]3 years ago

7 0

Answer: by a factor of √2

Explanation:

The kinetic energy is written as:

K = (m/2)*v^2

where m is the mass of the particle and v is the velocity:

If we double the kinetic energy, we have:

k' = 2k = 2(m/2)*v^2

now we want to see by what factor is increased the velocity, so we must put that 2 inside the square power, this is:

k' = 2*(m/2)*(v)^2 = (m/2)*(√2*v)^2 is the new kinetic energy,

This means that the velocity is increased by a factor of √2

Nady [450]3 years ago

6 0

<span> velocity increases by √3</span>

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Answer:

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Explanation:

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3 years ago

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Automobiles must be able to sustain a frontal impacl The automobile design must allow low speed impacts with little sustained da

valentinak56 [21]

Answer: the effective design stiffness required to limit the bumper maximum deflection during impact to 4 cm is 3906250 N/m

Explanation:

Given that;

mass of vehicle m = 1000 kg

for a low speed test; V = 2.5 m/s

bumper maximum deflection = 4 cm = 0.04 m

First we determine the energy of the vehicle just prior to impact;

W_v = 1/2mv²

we substitute

W_v = 1/2 × 1000 × (2.5)²

W_v = 3125 J

now, the the effective design stiffness k will be:

at the impact point, energy of the vehicle converts to elastic potential energy of the bumper;

hence;

W_v = 1/2kx²

we substitute

3125 = 1/2 × k (0.04)²

3125 = 0.0008k

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k = 3906250 N/m

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3 0

3 years ago

Potassium is a crucial element for the healthy operation of the human body. Potassium occurs naturally in our environment and th

Mariulka [41]

Answer:

a) 0.0288 grams

b) $2.6*10^{-10} J/kg$

Explanation:

Given that:

A typical human body contains about 3.0 grams of Potassium per kilogram of body mass

The abundance for the three isotopes are:

Potassium-39, Potassium-40, and Potassium-41 with abundances are 93.26%, 0.012% and 6.728% respectively.

Thus; a person with a mass of 80 kg will posses = 80 × 3 = 240 grams of potassium.

However, the amount of potassium that is present in such person is :

0.012% × 240 grams

= 0.012/100 × 240 grams

= 0.0288 grams

the effective dose (in Sieverts) per year due to Potassium-40 in an 80- kg body is calculate as follows:

First the Dose in (Gy) = $\frac{energy \ absorbed }{mass \ of \ the \ body}$

= $\frac{1.10*10^6*1.6*10^{-14}}{80}$

= $2.2*10^{-10} \ J/kg$

Effective dose (Sv) = RBE × Dose in Gy

Effective dose (Sv) = $1.2 *2.2*10^{-10} \ J/kg$

Effective dose (Sv) = $2.6*10^{-10} J/kg$

5 0

3 years ago

What is the size of the smallest vertical plane mirror in which a 6 ft tall person standing erect can see her full-length image?

Alex Ar [27]

Answer:

3 ft

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3 years ago

A 25 kg child stands 2.5 m from the center of a frictionless merry‐go‐round, which has a 200 kg*m^2 moment of inertia and is spi

vodka [1.7K]

Answer:

Explanation:

a ) Time period T = 2 s

Angular velocity ω = 2π / T

= 2π / 2 = 3.14 rad /s

Initial moment of inertia I₁ = 200 + mr²

= 200 + 25 x 2.5²

=356.25

Final moment of inertia

I₂ = 200 + 25 X 1.5 X 1.5

= 256.25

b ) We apply law of conservation of momentum

I₁ X ω₁ = I₂ X ω₂

ω₂ = I₁ X ω₁ / I₂

Putting the values

$w_2=\frac{356.25\times3.14}{256.25}$

ω₂ = 4.365 rad s⁻¹

c ) Increase in rotational kinetic energy

=1/2 I₂ X ω₂² - 1/2 I₁ X ω₁²

.5 X 256.25 X 4.365² - .5 X 356.25 X 3.14²

= 684.95 J

This energy comes from work done against the centripetal pseudo -force.

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3 years ago