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2 years ago

Help please, I really don’t know the answers

Physics

2 answers:

Allisa [31]2 years ago

4 0

The awnser should be A because the lines start there and end at the other side

Vesna [10]2 years ago

3 0

The answer is B. Hope this helps

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A 720 kg roller-coaster starts off from Location A. Assuming friction does not impede the car's motion, what will be the change

vaieri [72.5K]

We know, Potential Energy = m * g * h
Here, mass & gravity would be same, but their height will change so it will be:

ΔU = U₂ - U₁
ΔU = mgh₂ - mgh₁
ΔU = mg (h₂ - h₁)

Hope this helps!

7 0

2 years ago

Read 2 more answers

Two boats start together and race across a 48-km-wide lake and back. boat a goes across at 48 km/h and returns at 48 km/h. boat

jolli1 [7]

Answer:

Time required by boat 1 for the round trip is less than that of boat 2.

Hence, boat 1 wins.

Explanation:

Case 1: Boat 1

Speed of boat = $\frac{distance of river}{time}$

time = $\frac{distance of river}{speed of boat}$

While going to another end

time = $\frac{distance of river}{speed of boat}$

time = $\frac{48}{48}$

time = 1 hour

While going back,

time = $\frac{distance of river}{speed of boat}$

time = $\frac{48}{48}$

time = 1 hour

Total time taken by boat 1 is,

Total time by boat 1 = 1 hour + 1 hour = 2 hour

Total time by boat 1 = 2 hour

Total time taken by boat 1 for the round trip is 2 hour.

Case 2: Boat 2

Speed of boat = $\frac{distance of river}{time}$

time = $\frac{distance of river}{speed of boat}$

While going to another end

time = $\frac{distance of river}{speed of boat}$

time = $\frac{48}{24}$

time = 2 hour

While going back,

time = $\frac{distance of river}{speed of boat}$

time = $\frac{48}{72}$

time = 0.66 hour

Total time taken by boat 2 is,

Total time by boat 1 = 2 hour + 0.66 hour

Total time by boat 1 = 2.66 hour

Total time taken by boat 2 for the round trip is 2.66 hour.

Time required by boat 1 for the round trip is less than that of boat 2.

Hence, boat 1 wins.

5 0

3 years ago

2. What is the wavelength of the wave shown above?<br> a. 6m<br> b. 11<br> C 2m<br> d. 3m

Dafna1 [17]

Answer:

網站有中、英文版本，也有繁、簡體版，可通過每頁左上角的連結隨時網站有中、英文版本，也有繁、簡體版，可通過每頁左上角的連結隨時

Explanation:

7 0

2 years ago

People's perceptions of what is important in life are known as:

tangare [24]

Social perception (or person perception) is the study of how people form impressions of and make inferences about other people as sovereign personalities.A real-world example of social perception is understanding that others disagree with what one said when one sees them roll their eyes.

6 0

2 years ago

(30 Points) A piston–cylinder arrangement containing Nitrogen (N2), initially at 4 bar and 438 K, undergoes an expansion to a fi

BartSMP [9]

Answer:

A. Final pressure P2

P2/P1 = (T2/T1)^n/n-1

P1 = 4bar

T1 = 438K

T2 = 300K

Polytropic index, n, = 1.3

P2 = 4 (300/438)^1.3/1.3-1

P2 = 4 (300/438)^4.333

P2 = 4 * 0.19400

P2 = 0.776bar.

B. The work done is;

W = mR/ n-1 (T1 -T2)

Where, R = 0.1889kJ/kg.K, m = 1

W = 1 * 0.1889/ 1.3-1 * (438-300)

W = 86.89kJ/kg.

C. The heat transfer, Q

Q = W + ΔU

Q = W + mCv(T2-T1), where Cv of nitrogen is 0.743kj/kgk

Q = 86.89 + 1 * 0.743 (300-438)

Q = 86.89 + (-102.534)

Q = -15.644kJ/K

Q = 15.64kJ/K

3 0

2 years ago