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bearhunter [10]
3 years ago
10

A train whose proper length is 1200 m passes at a high speed through a station whose platform measures 900 m, and the station ma

ster observes that when the train passes it occupies exactly the entire length of the platform. What is the speed of the train?
Physics
1 answer:
TiliK225 [7]3 years ago
6 0

Answer:

0.66c

Explanation:

Use length contraction equation:

L = L₀ √(1 − (v²/c²))

where L is the contracted length,

L₀ is the length at 0 velocity,

v is the velocity,

and c is the speed of light.

900 = 1200 √(1 − (v²/c²))

3/4 = √(1 − (v²/c²))

9/16 = 1 − (v²/c²)

v²/c² = 7/16

v = ¼√7 c

v ≈ 0.66 c

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. A water balloon is thrown horizontally at a speed of 2.00 m/s from the roof of a building that is 6.00m above the ground. At t
dedylja [7]

Answer:

Explanation:

Height of building

H = 6m

Horizontal speed of first balloon

U1x = 2m/s

Second ballot is thrown straight downward at a speed of

U2y = 2m/s

Time each gallon hits the ground

Balloon 1.

Using equation of free fall

H = Uoy•t + ½gt²

Uox = 0 since the body does not have vertical component of velocity

6 = ½ × 9.8t²

6 = 4.9t²

t² = 6 / 4.9

t² = 1.224

t = √1.224

t = 1.11 seconds

For second balloon

H = Uoy•t + ½gt²

6 = 2t + ½ × 9.8t²

6 = 2t + 4.9t²

4.9t² + 2t —6 = 0

Using formula method to solve the quadratic equation

Check attachment

From the solution we see that,

t = 0.9211 and t = -1.329

We will discard the negative value of time since time can't be negative here

So the second balloon get to the ground after t ≈ 0.92 seconds

Conclusion

The water ballon that was thrown straight down at 2.00 m/s hits the ground first by 1.11 s - 0.92s = 0.19 s.

4 0
3 years ago
Read 2 more answers
A bubble, located 0.200 m beneath the surface in a glass of beer, rises to the top. The air pressure at the top is 1.01 ???? 10
SIZIF [17.4K]

Answer:

the ratio of the bubble’s volume at the top to its volume at the bottom is 1.019

Explanation:

given information

h = 0.2 m

P_{0} = 1.01  x 10^{5} Pa

P_{1} V_{1} = P_{2} V_{2}

\frac{V_{2} }{V_{1}} = \frac{P_{1} }{P_{2}}

P_{1}  = P_{0}  + ρgh, ρ = 1000 kg/m^{3}

P_{1}  = 1.01 x 10^{5} Pa + (1000 x 9.8 x 0.2) = 1,0296 x 10^{5} Pa

P_{2}  = P_{0}  = 10^{5} Pa

thus,

\frac{V_{2} }{V_{1}} = 1,0296 x [tex]10^{5}/10^{5} = 1.019

8 0
3 years ago
A powerful motorcycle can produce an acceleration of 3.00 m/s2 while traveling at 106.0 km/h. At that speed, the forces resistin
otez555 [7]

Answer:

"1155 N" is the appropriate solution.

Explanation:

Given:

Acceleration,

a=3 \ m/s^2

Forces resisting motion,

F_f=432 \ N

Mass,

m = 241 \ kg

By using Newton's second law, we get

⇒ F-F_f=ma

Or,

⇒         F=ma+F_f

By putting the values, we get

⇒             =(3\times 241)+432

⇒             =723+432

⇒             =1155 \ N

7 0
3 years ago
The bulk modulus of water is 2.2 x 109 Pa, and its density is 1.0 x 103 kg/m3. What is the speed of sound in water?
yarga [219]

hi guys! Lets be friends!

7 0
3 years ago
Which best describes the energy of a sound wave as it travels through a medium
Solnce55 [7]
C. It depends on the medium
3 0
3 years ago
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