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3 years ago

A light bulb has a power output of 80 W and it has been left on for 90 seconds. How much work was done?

1 answer:

3 0

7200 joules of heat and light energy was dissipated into the air. But no work was done ... no force moved through no distance.

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A 110 kg ice hockey player skates at 3.0 m/s toward a railing at the edge of the ice and then stops himself by grasping the rail

velikii [3]

Answer:

Δ KE = -495 J

Explanation:

given,

mass of the ice hockey player = 110 Kg

initial speed = 3 m/s

final speed = 0 m/s

distance, d = 0.3 m

change in kinetic energy

$\Delta K E = \dfrac{1}{2}mv_f^2 - \dfrac{1}{2}mv_i^2$

$\Delta K E = \dfrac{1}{2}mv(0)^2 - \dfrac{1}{2}\times 110\times 3^2$

Δ KE = -495 J

Hence, the change in kinetic energy is equal to Δ KE = -495 J

7 0

3 years ago

6. What is the molar mass of H2O?

kotykmax [81]

Answer:

a) 18.015

Explanation:

I Googled it, hope this helped

7 0

3 years ago

Please hurry!!!!!!!.......

elixir [45]

Answer:

Explanation:

D is nonsense. The current keeps coming through all lights.

A is wrong. The exact opposite happens. More bulbs more resistance.

C is wrong. More resistance less current, not more.

So your answer is B because the voltage drop in each decreases when there are more bulbs.

5 0

3 years ago

Read 2 more answers

Three resistors, 21 Ω, 58 Ω, and 64 Ω, are connected in series, and a 0.50-A current passes through them. What are (a) the equiv

adoni [48]

<h2>a) Equivalent resistance is 143 Ω</h2><h2>b) Potential difference is 71.5 V</h2>

Explanation:

When resistors are connected in series, effective resistance is given by

$R_{eff}=R_1+R_2+R_3+......$

Here

R₁ = 21Ω

R₂ = 58Ω

R₃ = 64Ω

a) $R_{eff}=R_1+R_2+R_3\\\\R_{eff}=21+58+64\\\\R_{eff}=143\Omega$

Equivalent resistance is 143 Ω

b) We know

Potential difference = Current x Resistance

V = IR

I = 0.5 A

R = 143Ω

Substituting

V = 0.5 x 143 = 71.5 V

Potential difference is 71.5 V

6 0

3 years ago

Help it’s due tomorrow

Sati [7]

Answer:

A., the variables have a direct relationship.

Explanation:

As K rises, L rises.

It's not B. because one isn't rising as the other is lowering.

It's not C. because undefined would be a vertical line.

4 0

3 years ago