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3 years ago

What does the law of conservation of energy state?

Physics

1 answer:

sergij07 [2.7K]3 years ago

4 0

A because energy can not be created or destroyed ONLY transformed from one from of energy to another

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A substance burns in the presence of oxygen.

valina [46]

If I don’t know a answer I put C bc it is a 50/50 chance but it might be wrong

5 0

3 years ago

Read 2 more answers

A proton is placed at point A, where the electric potential is 100 V . The proton is released from rest. Some time later, the p

kap26 [50]

To develop this problem it is necessary to apply the concepts related to electromagnetic energy and Broglie's hypothesis.

By definition we know that the electrical energy of a proton can be expressed as

E = qV

Where,

q = Charge of proton

V = Voltage

Replacing with our values

E = qV

$E = (1.6*10^{-19})(220) \rightarrow$ It is necessary to add the two potentials

$E = 4.224*10^{-17}J$

From Broglie's hypothesis we know that the wavelength is given by

$\lambda = \frac{h}{P}$

Where,

h = Planck's constant

p = Momentum

The momentum of a particle can be expressed in terms of energy, that is,

$P = \sqrt{E*2m}$

Where,

m = mass

E = Energy (potential or kinetic)

Therefore replacing this value at lambda,

$\lambda = \frac{h}{\sqrt{E*2m}}$

$\lambda = \frac{6.625*10^{-34}}{\sqrt{(4.224*10^{-17})*2(1.67*10^{-27})}}$

$\lambda = 1.763*10^{-12}m$

7 0

3 years ago

A beam is pivoted at one end, as shown.

lara31 [8.8K]

The answer is C upwards at 20cm

7 0

3 years ago

6. If a bicyclist, with initial velocity of zero, steadily gained speed until reaching a final velocity of 39m/s, how far would

Bezzdna [24]

Answer:

175 m

Explanation:

The average velocity for constant acceleration is the average of the beginning and ending velocities. That is (0+39)/2=19.5 m/s. If the bicyclist rides for 9 seconds, the distance traveled is ...

(9 s)(19.5 m/s) = 175.5 m

She would travel 175.5 meters in that time.

7 0

4 years ago

A solid steel bar of circular cross section has diameter d 5 2.5 in., L 5 60 in., and shear modulus of elasticity G 5 11.5 3 106

8090 [49]

Answer:

A) θ = 4.9 x 10^(-3) rad

B) τ_max = 1.173 ksi

C) τ_a = 4.786 ksi

Explanation:

We are given;

diameter; d = 2.5 inches = 0.2083 ft

Length; L = 60 inches = 5 ft

Torque; T = 300 lb.ft

Shear modulus; G = 11.5 x 10^(6) psi = 11.5 x 144 x 10^(6) lb/ft² = 1.656 x 10^(9) lb/ft²

A) Now, formula to determine angle of twist is given as;

T/I_p = Gθ/L

Where I_p is polar moment of inertia

θ is angle of twist.

Now I_p = πd⁴/32 = π(0.2083)⁴/32 = 1.85 x 10^(-4) ft⁴

Thus, making θ the subject, we have;

TL/GI_p = θ

θ = (300 x 5)/(1.656 x 10^(9) x 1.85 x 10^(-4))

θ = 4.9 x 10^(-3) rad

B) Maximum shear stress is given by the formula ;

τ_max = (Gθ/L)(d/2)

From earlier, (Gθ/L) = T/I_p

Thus, (Gθ/L) = 300/1.85 x 10^(-4) = 1621621.6216

Thus,

τ_max = 1621621.6216 x (0.2083/2)

τ_max = 168891.89 lbf/ft²

Converting to ksi = 168891.89/144000 ksi = 1.173 ksi

C) Shear stress at radial distance is given as;

τ_a = (Gθ/L)•r_a

r_a is given as 5.1 inches = 0.425m

τ_a = 1621621.6216 x 0.425 = 689189.189 lbf/ft²

Converting to ksi = 689189.189/144000 ksi = 4.786 ksi

7 0

3 years ago