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3 years ago

2 b (ignore what I already completed)

Physics

1 answer:

posledela3 years ago

4 0

Answer:

The answer for this question is it talks about the circuit containing the led, switch and all that

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Sedaia [141]

Answer:

10 mL= 0.01 L

Explanation:

V(water) = 20 mL

V(water + a marble) = 30 mL

V(marble) = V(water + a marble) - V(water) = 30 mL - 20 mL = 10 mL= 0.01 L

6 0

4 years ago

Which is an example of a chemical reaction ?

julia-pushkina [17]

Answer:

paper burned and turned into smoke...

Explanation:

When a chemical reaction has taken place that means that whatever the starting variable is, (in this case it was the paper) then it cannot go back to its original state... you can also tell if a chemical reaction has taken place if the test releases any kind of gas, if there is a temperature change, or if there is a color change. Which this time it changed from paper into smoke which is a gas

Hope This Helps

8 0

4 years ago

Read 2 more answers

If the magnitude of the magnetic force on a proton is F when it is moving at 14.0 o with respect to the field, what is the magni

sergeinik [125]

Answer:

The magnitude of the magnetic force at 32.5⁰ to the field, is 2.22 F

Explanation:

Given;

magnitude of the magnetic force is F at 14.0⁰ with respect to the field.

To determine the magnitude of the magnetic force at 32.5⁰ to the field, we apply the following formula and solve with proportion;

f*Sin(14.0⁰) = F

f*Sin(32.5⁰) = ?

$= \frac{f*Sin(32.5^o)}{f*Sin(14.0^o)}.F\\\\ =2.22 \ F$

Therefore, the magnitude of the magnetic force at 32.5⁰ to the field, is 2.22 F

6 0

4 years ago

A driver sets out on a journey. for the first half of the distance she drives at the leisurely pace of 30 mi/h; during the secon

Gemiola [76]

The average speed of a moving object is the rate of change of a certain distance with respect with time. It is equal to the total distance that was traveled by the object over the total time it takes to travel that distance. For this problem we need to assume that the total distance that was traveled would be equal to 120 miles. So, for the first half of the distance or 60 miles at a speed of 30 miles per hour, the time taken would be two hours. For the remaining 60 miles at a speed of 60 miles per hour, 1 hour is total time traveled. So, we calculate the average speed as follows:

Average speed = total distance / total time
Average speed = 120 miles / 2 hr + 1 hr
Average speed = 40 mi / hr

5 0

4 years ago

Annealing is a process by which steel is reheated and then cooled to make it less brittle. Consider the reheat stage for a 100-m

Anit [1.1K]

Complete question is;

Annealing is a process by which steel is reheated and then cooled to make it less brittle. Consider the reheat stage for a 100 mm thick plate (ρ = 7830 kg/m³, Cp = 550 J/Kg.K, k = 48 W/m K). The plate initially is at 200 °C and is to be heated to a minimum temperature of 550 °C. Heating is effected in a gas-fired furnace where the products of combustion at T∞ = 800 °C maintain a convection heat transfer coefficient of h = 250 W/m.K on both surfaces of the plate. How long should the plate be left in the furnace?

Answer:

860 seconds

Explanation:

We are given;

Initial Temperature; T_i = 200 °C

Minimum Temperature; T_o = 550 °C

T∞ = 800 °C

convection coefficient; h = 250 W/m².K

ρ = 7830 kg/m³

Cp = 550 J/kg K

k = 48 W/m K

Plate thickness = 100mm

Thus,L = 100/2 = 50mm = 0.05 m

Let's find the biot number from the formula;

Bi = hL/K

Bi = (250 × 0.05)/48

Bi = 0.2604

Now, lowest temperature in the slab is given as;

θ_o = (T_o - T∞)/(T_i - T∞)

θ_o = (550 - 800)/(200 - 800)

θ_o = 0.4167

Now, from online tables calculation, we can find the root of the biot number.

Thus, root of the biot number Bi = 0.2604 is;

ζ1 = 0.488 rad

Also, C1 is gotten as 1.0396

Now,formula for thermal diffusivity is;

α = k/ρc

α = 48/(7830 × 550)

α = 1.115 × 10^(-5) m²/s

Also, from online tables, f(ζ1) = 0.401

Thus, we can find the time the plate should the plate be left in the furnace from;

-(ζ1)²(αt/L²) = In 0.401

-(ζ1)²(αt/L²) = -0.9138

t = (-0.9138 × 0.05²)/-(0.488² × 1.115 × 10^(-5))

t ≈ 860 s

3 0

3 years ago