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3 years ago

- Thermal Energy Test

1 answer:

4 0

Answer:D. The metal in the door expands when it becomes warm due to an increase in kinetic energy, and contracts when it's cooler.

Explanation:

because the metal in the door expands due to warm to an increase in kinetic energy and contracts.

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A 17-car train standing on the siding is started in motion by the train’s engine. 9 cm slack is between each of the cars, which

BaLLatris [955]

Answer:

4 seconds

Explanation:

There are links between cars, they are in between

1-2, 2-3, 3-4, 4-5, 5-6, 6-7, 7-8, 8-9, 9-10, 10-11, 11-12, 12-13, 13-14, 14-15, 15-16, 16-17.

Here 1 represents the first car which is firmly attached to the engine. So, there are 16 links and each link has a slack of 9 m.

So, total slack

9×16 = 144 cm

Speed of train = 36 cm/s

$\text{Time taken by the pulse}=\frac{Length}{speed}\\\Rightarrow \text{Time taken by the pulse}=\frac{144}{36}\\\Rightarrow \text{Time taken by the pulse}=4\ s$

Time taken by the pulse to travel the length of train is 4 seconds.

6 0

3 years ago

A spacecraft orbits the Earth at height of 1600km. Calculate the escape velocity for the spacecraft.

guapka [62]

Answer:

what do u need help with

Explanation:

Calculate the escape velocity for the spacecraft. [G= 6.67×10^-11Nm^2kg^-2, mass of the Earth= 5.97×10^24kg, radius of the Earth= ...

7 0

3 years ago

Which one of the following does not accurately describe the universal gravitational law? Question 10 options: A) Gravitational f

just olya [345]

Answer:

Choice C seems to be the right answer.

Explanation:

5 0

3 years ago

Read 2 more answers

To qualify to run in the 2005 Boston Marathon, a distance of 26.2 miles, an 18-year-old woman had to have completed another mara

Korvikt [17]

Answer:

7,14545 mph and 3,1936 m/s

Explanation:

The average speed is calculated by dividing the displacement over time, then it is 26,2 miles/(3 2/3 hours), here 3 (2/3) hours is a mixed number, that represents 11/3 hours or 3,66 hours. Then the average speed is 7,14545 mph, now to turn this into meters per second, we notice as mentioned that 1 mile =1609 meters and 1 hour=3600 seconds. Then 7,14545 miles/hour* (1 hour/3600 seconds) * (1609 meters/1 mile)=3,1936 m/s

3 0

3 years ago

Two blocks, A and B, are connected by a rope. A second rope is connected to block B and a steady, horizontal tension force of T

Oksanka [162]

Answer:

40 N

Explanation:

We are given that

Speed of system is constant

Therefore, acceleration=a=0

Tension applied on block B=T=50 N

Friction force=f=10 N