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2 years ago

The total power input to the LED was 0.24 W.

Physics

1 answer:

just olya [345]2 years ago

4 0

Answer: How do you calculate useful power output?

Explanation: Hence, useful energy output:

Wuseful=F×d=10×5=50 J W useful = F × d = 10 × 5 = 50 J. ...

Ewasted=65−50=15 J E wasted = 65 − 50 = 15 J. ...

Efficiency=Useful energy outputTotal energy input×100%=5065×100%=76.9% Efficiency = Useful energy output Total energy input × 100 % = 50 65 × 100 % = 76.9 %

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Find the mass of a sample of water if its temperature dropped 24.8 °C when it lost 870 J of

rosijanka [135]

Answer:

8.35 × $10^{-3}$ kg

Explanation:

Remember the formula for heat:

$Q=mc\Delta T$

You just need to solve for m, doing so you're left with:

$m=\dfrac{Q}{c\Delta T}$

Replace the variables with numbers and that's it.

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2 years ago

At a stoplight, a truck traveling at 15 m/s passes a car as it starts from rest. The truck travels at constant velocity and the

Art [367]

The time that the car take to catch up to truck would be :

1/2 ar^2 = vt

1/2 (3) t^2 = 15t

1.5 t^2 = 15t

t ^2 = 10s

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4 0

3 years ago

What is a compound composed of two elements that share valence electrons?

ExtremeBDS [4]

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5 0

3 years ago

Read 2 more answers

Two carts, A and B, are connected by a spring and sitting at rest on a track. Cart A has a mass of 0.4 kg and Cart B has a mass

Ilya [14]

Both carts experience the same force but Cart A has a greater speed after the recoil.

The given parameters;

Mass of the cart A = 0.4 kg
Mass of the cart B = 0.8 kg

Apply the principle of conservation of linear momentum to determine the velocity of the carts after collision;

$m_Av_0_A\ + m_Bv_0_B = m_Av_f_A \ + m_Bv_f_B\\\\the \ initial \ velocity \ of \ both \ carts = 0\\\\0.4(0) + 0.8(0) = 0.4v_f_A + 0.8v_f_B\\\\0 = 0.4v_f_A + 0.8v_f_B\\\\0.4v_f_A = -0.8v_f_B\\\\v_f_A= \frac{-0.8 v_f_B}{0.4} \\\\v_f_A = - 2 \ v_f_B \ \ m/s$

According to Newton's third law of motion, action and reaction are equal and opposite. The force exerted on cart A is equal to the force exerted on cart B but in opposite direction.

$F_A = -F_B$

Thus, the correct statement that compares the motion and forces acting on the two carts is "Both carts experience the same force but Cart A has a greater speed after the recoil."

Learn more about conservation of linear momentum here: brainly.com/question/7538238

6 0

2 years ago

500 g of water at 90°C is cooled in a freezer. If all the water is converted to ice, what is the amount of heat released when th

KATRIN_1 [288]

Answer:

356 000 J

Explanation:

Total Energy released

= Energy released when water cools to 0 + Energy released when water is converted to ice at 0

= mcT + ml

= (0.5)(4200)(90-0) + (0.5)(334 000)

= 189 000 J + 167 000 J

= 356 000 J

4 0

3 years ago