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3 years ago

A wagon is accelerating down a hill. Which statement is true?

1 answer:

3 0

Potential energy decreases and kinetic energy increases.

Potential energy is related to the height, since the wagon is going downhill, height decreases and potential energy decreases.

Kinetic energy is related to the speed, since the wagon is speeding up, kinetic energy increases.

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Does red or green light have more energy.

dalvyx [7]

Answer: Green Light

Explanation:

The color green has a higher frequency than the color red and the higher the frequency the more energy. If you looks at a rainbow you'll see red on one end and violet on the other. Red has the least energy Violet has the most.

7 0

2 years ago

A car is designed to get its energy from a rotating

nydimaria [60]

Answer:

(a). The kinetic energy stored in the fly wheel is 46.88 MJ.

(b). The time is 1.163 hours.

Explanation:

Given that,

Radius = 1.50 m

Mass = 475 kg

Power $P= 15.0 hp = 15.0\times746=11190 watt$

Rotational speed = 4000 rev/min

We need to calculate the moment of inertia

Using formula of moment of inertia

$I=\dfrac{1}{2}mr^2$

Put the value into the formula

$I=\dfrac{1}{2}\times475\times(1.50)^2$

$I=534.375\ kg m^2$

(a). We need to calculate the kinetic energy stored in the fly wheel

Using formula of K.E

$K.E=\dfrac{1}{2}I\omega^2$

Put the value into the formula

$K.E = \dfrac{1}{2}\times534.375\times(4000\times\dfrac{2\pi}{60})^2$

$K.E=46880620.9\ J$

$K.E =46.88\times10^{6}\ J$

$K.E =46.88\ MJ$

(b). We need to calculate the length of time the car could run before the flywheel would have to be brought backup to speed

Using formula of time

$t=\dfrac{46.88\times10^{6}}{11190}$

$t=4189.45\ sec$

$t=1.163\ hours$

Hence, (a). The kinetic energy stored in the fly wheel is 46.88 MJ.

(b). The time is 1.163 hours.

3 0

3 years ago

Coulomb's law is expressed mathematically as

nataly862011 [7]

Force between two charges =

( 1/4πε₀ ) · (Charge #1) · (Charge #2) / (Distance between them)²

in the direction away from each other.

In other words, if the force is positive, the charges are repelling.
If the force is negative, the charges are attracting.

4 0

3 years ago

Which circuit is a series circuit

posledela

Answer:

The answer is A

Explanation:

7 0

3 years ago

Two strings with linear densities of 5 g/m are stretched over pulleys, adjusted to have vibrating lengths of 0.50 m, and attache

HACTEHA [7]

Answer:

2.18 kg

Explanation:

The frequency of a wave in a stretched string f = n/2L√(T/μ) where n = harmonic number, L = length of string, T = tension = mg where m = mass of object on string and g = acceleration due to gravity = 9.8 m/s² and μ = linear density of string.

For string 1, its fundamental frequency f is when n = 1. So,

f = 1/2L√(T/μ) = 1/2L√(mg/μ)

Now for string 1, L = 0.50 m, m = 20 kg and μ = 5 g/m = 0.005 kg/m

substituting the values of the variables into f, we have

f = 1/2L√(mg/μ)

f = 1/2 × 0.50 m√(20 kg × 9.8 m/s²/0.005 kg/m)

f = 1/1 m√(196 kgm/s²/0.005 kg/m)

f = 1/1 m√(39200 m²/s²)

f = 1/1 m × 197.99 m/s

f = 197.99 /s

f = 197.99 Hz

f ≅ 198 Hz

For string 2, at its third harmonic frequency f' is when n = 3. So,

f' = 3/2L√(T/μ) = 3/2L√(mg/μ)

Now for string 2, L = 0.50 m, m = M kg and μ = 5 g/m = 0.005 kg/m

substituting the values of the variables into f, we have

f' = 3/2L√(Mg/μ)

f' = 3/2 × 0.50 m√(M × 9.8 m/s²/0.005 kg/m)

f' = 3/1 m√(M1960 m²/s²kg)

f' = 3/1 m√M√(1960 m²/s²kg)

f' = 3/1 m √M × 44.27 m/s√kg

f' = 132.81√M/s√kg

f' = 132.81√M Hz/√kg

Since the frequency of the beat heard is 2 Hz,

f - f' = 2 Hz

So, 198 Hz - 132.81√M Hz/√kg = 2 Hz

132.81√M Hz/√kg = 198 Hz - 2 Hz

132.81√M Hz/√kg = 196 Hz

√M Hz/√kg = 196 Hz/138.81 Hz

√M/√kg = 1.476

squaring both sides,

[√M/√kg] = (1.476)²

M/kg = 2.178

M = 2.178 kg

M ≅ 2.18 kg

8 0

3 years ago