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3 years ago

Undersoil electrical heating systems are used in greenhouses. This system could also be

Physics

1 answer:

Nata [24]3 years ago

4 0

Answer:t

Explanation:

Given that,

Power output is

P = 0.50kW = 0.5 × 1000 = 500W.

We want to find energy transfer in

t = 2minutes = 2 × 60 = 120 seconds

Also, time to hour

t = 2/60 = 1/30 hour

Power is the rate of energy.

Therefore,

Power = energy / time taken

Energy = power × time taken

Energy = 0.5kW × 1/30 hr

Energy = 0.01667 kWh

Also, energy in Joule

Energy = power × time

Energy = 500W × 120s

Energy = 60,000J

Energy = 60kJ.

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Formula for percentage error

GarryVolchara [31]

Answer:

PE = (|accepted value – experimental value| \ accepted value) x 100%

Explanation:

7 0

3 years ago

James and John dive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running s

liraira [26]

Answer:

Both of them reach the lake at the same time.

Explanation:

We have equation of motion s = ut + 0.5at²

Vertical motion of James : -

Initial velocity, u = 0 m/s

Acceleration, a = g

Displacement, s = h

Substituting,

s = ut + 0.5 at²

h = 0 x t + 0.5 x g x t²

$t_{James}=\sqrt{\frac{2h}{g}}$

Vertical motion of John : -

Initial velocity, u = 0 m/s

Acceleration, a = g

Displacement, s = h

Substituting,

s = ut + 0.5 at²

h = 0 x t + 0.5 x g x t²

$t_{John}=\sqrt{\frac{2h}{g}}$

So both times are same.

Both of them reach the lake at the same time.

3 0

3 years ago

A skateboarder is moving 5.25 m/s when he starts to roll up a frictionless hill. How much higher is he when his velocity has red

Taya2010 [7]

Mechanical energy E = mgh + 1/2mv²

When he starts, let h = 0 ⇒ E₁ = 1/2mv₁²
When he reaches height h ⇒ E₂ = mgh + 1/2mv₂²

Without friction, energy is conserved at all times.

E₁ = E₂
↓
1/2mv₁² = mgh + 1/2mv₂²
↓
1/2v₁² = gh + 1/2v₂²
↓
gh = 1/2(v₁² - v₂²)
↓
h = (v₁² - v₂²) / (2g)

5 0

3 years ago

Read 2 more answers

66 POINTS! Which is true about the four atoms shown in figures A, B, C, and D?

Butoxors [25]

Answer:

Explanation:

A and B are isotopes of one another but the same element

C and D are isotopes of one another but the same element

However, A and B have a different proton count than C and D, indicating different elements because the proton count is equivalent to the atomic number.

6 0

3 years ago

Read 2 more answers

three resistors which values of 15 ohm 40 ohm 60 ohm respectively are connected in parallel. what is their equivalent resistance

VashaNatasha [74]

1) Equivalent resistance, 1/R = 1/15 + 1/40 + 1/60 = 8+3+2 /120 = 13/120

R = 120/13 = 9.23

2) Current, I = V/R = 115/9.23 = 12.45 A

7 0

3 years ago