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3 years ago

In the first law of Thermodynamics ΔE = Q - W, what does ΔE stand for???

2 answers:

7 0

ΔE = q + w

q = heat (quantity of)

q and w can be positive or negative depending on if work/heat is being absorbed/done on the system or released/done by the system

Gnesinka [82]3 years ago

3 0

It is D. hope this helped!!!!

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John has a boat that will travel at the rate of 15 kph in still water. he can go upstream for 35 km in the same time it takes to

MA_775_DIABLO [31]

Let F = the downstream speed of the water.

Then the boat's upstream speed is: 15 - F 
The boat's downstream speed is: 15 + F 

Assume both the journeys mentioned take T hours, then using "speed x time = distance" we get: 

Downstream journey: (15 + F)T = 140 
Upstream journey: (15 - F)T = 35 

Add the two formulae together: 

(15 + F)T + (15 - F)T = 140 + 35 

15T + FT + 15T - FT = 175 

30T = 175 

T = 35/6 

Use one of the equations to find F: 

(15 + F)T = 140 

15 + F = 140/T 
F = 140/T - 15 
F = 140/(35/6) - 15 
F = 24 - 15 
F = 9 

i.e. the downstream speed of the water is 9 kph 

Therefore, the boat's speed downstream is 15 + F = 15 + 9 = 24 kph.
the answer is: *24kph*

5 0

4 years ago

A typical laboratory centrifuge rotates at 3700 rpm . Test tubes have to be placed into a centrifuge very carefully because of t

Alexus [3.1K]

Answer:

Explanation:

acceleration of test tube

= ω² R

= (2πn)² R

= 4π²n²R

n = no of rotation per second

= 3700 / 60

= 61.67

R = .10 m

acceleration

= 4π²n²R

= 4 x 3.14² x 61.67² x .10

= 14999 N Approx

3 0

3 years ago

What is transferred by all types of waves? A. energy B. electrons C. heat D. matter

djyliett [7]

The question is what do all types of waves transfer. Waves, both mechanical and electromagnetic are disturbances that transfer energy without transporting matter. It doesnt matter wether they are propagating trough a medium or trough vacuum. Therefore the correct answer is A. energy.

3 0

3 years ago

Read 2 more answers

Which of these steps would most likely be part of a lab procedure?

Snezhnost [94]

Answer:

These are a part of lab procedures:

1. Write a hypothesis to answer a question.

2. Write a title at the top of a completed lab report.

3. Record the time to complete a chemical reaction.

These are NOT a part of lab procedures:

1. Create a question on the cause of a chemical reaction.

8 0

3 years ago

Let’s say I am in a bumper car and have a velocity of 14 m/s, driving in the positive x-direction. I and my bumped car have a ma

AlekseyPX

Answer:

160 kg

12 m/s

Explanation:

$m_1$ = Mass of first car = 120 kg

$m_2$ = Mass of second car

$u_1$ = Initial Velocity of first car = 14 m/s

$u_2$ = Initial Velocity of second car = 0 m/s

$v_1$ = Final Velocity of first car = -2 m/s

$v_2$ = Final Velocity of second car

For perfectly elastic collision

$m_{1}u_{1}+m_{2}u_{2}=m_{1}v_{1}+m_{2}v_{2}\\\Rightarrow m_2v_2=m_{1}u_{1}+m_{2}u_{2}-m_{1}v_{1}\\\Rightarrow m_2v_2=120\times 14+m_2\times 0-(120\times -2)\\\Rightarrow m_2v_2=1920\\\Rightarrow m_2=\frac{1920}{v_2}$

Applying in the next equation

$v_2=\frac{2m_1}{m_1+m_2}u_{1}+\frac{m_2-m_1}{m_1+m_2}u_2\\\Rightarrow v_2=\frac{2\times 120}{120+\frac{1920}{v_2}}\times 14+\frac{m_2-m_1}{m_1+m_2}\times 0\\\Rightarrow \left(120+\frac{1920}{v_2}\right)v_2=3360\\\Rightarrow 120v_2+1920=3360\\\Rightarrow v_2=\frac{3360-1920}{120}\\\Rightarrow v_2=12\ m/s$

$m_2=\frac{1920}{v_2}\\\Rightarrow m_2=\frac{1920}{12}\\\Rightarrow m_2=160\ kg$

Mass of second car = 160 kg

Velocity of second car = 12 m/s

5 0

4 years ago