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3 years ago

A student investigated how the mass of water in an electric kettle affected the time taken for the water to reach boiling point.

Physics

1 answer:

Sedbober [7]3 years ago

4 0

Answer:

1.because of the heat produced by the socat

2. they should have control how they placed the heater

3. because the water is to much

4.because is different from the question

5. because that is how the question is

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A four-cylinder gasoline engine has an efficiency of 28 % and delivers 280 J of work per cycle per cylinder. A) If the engine ru

Lorico [155]

Answer:

A). 28 $\frac{kJ}{s}$ at 25 cycles per second

B). 100 kJ

C). 6500s or 180.3 minutes or 1.8 hr

Explanation:

Four-cylinder= 280J cycleper cylinder

Efficiency =28%

A).

$W=280J (\frac{1}{cycle}*\frac{1}{cylinder} *\frac{4cylinder}{1} *\frac{25cycle}{s} )\\W=280J*100\frac{1}{s}\\ W=28000\\W=20x10^{3} = 28kJ$

W=28 $\frac{kJ}{s}$

B).

The efficiency is 28% and have a work of 28k0J

so:

If 20kJ⇒28%

xkJ ⇒ 100%

$100%*28kJ=xkJ*28%\\xkJ=\frac{100*28}{28}\\ x=100kJ$

Total heat is 100kJ

C).

130MJ per gallon

$t_{gallon}=\frac{130MJ}{20\frac{kJ}{s} }= \frac{130x10^{6} }{20x10^{3}}=6500s\\ 6500s*\frac{1minute}{60s}*\frac{1hr}{60minute}=1.8hr$

4 0

3 years ago

A car travels 40 miles north in 30 minutes and then turns around and travels 20 miles south in 30 minutes. The distance travelle

Pani-rosa [81]

Answer:

The distance traveled by the car is 60 miles and the displacement of the car is 20 miles in the north direction.

Explanation:

The distance is the total length of the car's path.

d = 40 mi + 20 mi

d = 60 mi

The displacement is the distance between the starting position and the final position.

x = (40 − 20) mi N

x = 20 mi N

7 0

3 years ago

The figure shows a graph of the angular velocity of a rotating wheel as a function of time. Although not shown in the graph, the

nataly862011 [7]

Answer:

θ = 33.54 rad

Explanation:

This is a circular motion exercise

θ= θ₀ + w₀ t + ½ α t²

suppose that for t = 0 the body is at its initial point θ₀ = 0 and from the graph we see that the initial angular velocity w₀ = -9.0 rad / s

we look for the angular acceleration,

α = $\frac{\Delta w}{ \Delta t}$

from the graph taken two points

α = $\frac{0 - (-9.0)}{3.0 - 0}$

α = 3 rad / s²

we substitute in the first equation

θ = 0 -9 t + ½ 3 t²

the displacement is requested for t = 8.6 s

θ = = -9 8.6 + 3/2 8.6²

θ = 33.54 rad

4 0

3 years ago

What particle moves around the nucleus and has a negative charge??

sasho [114]

I think you mean electrons

6 0

4 years ago

A 10 kg mass rests on a table. What acceleration will be generated when a force of 20 N is applied and encounters a frictional f

11Alexandr11 [23.1K]

The frictional force is oposing the force that we apply to this mass. Therefore the overall force is $F_{total}=F_{applied}-F_{friction}=20-15 =5 (Newton)$
The second principle of physics tells us that the acceleration of a mass is direct proportional to the applied force, the mass of that object being the proportionality constant.
$F=m*a$
Hence $a= \frac{F}{m}=5/10 =0.5 (m/s^2)$

6 0

3 years ago