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kobusy [5.1K]
3 years ago
7

A 63 kg ice skater finishes her performance and crossed the finish line with a speed of 10.8 m/s.

Physics
1 answer:
Mars2501 [29]3 years ago
4 0

Answer:

10.1 m/s

Explanation:

Every moving body or an object has a momentum. The simplest way to calculate it is to multiply the mass of an object with its velocity (p = m•v). So, just after this ice skater finished her performance, her momentum was 63 kg•10.8 m/s which equals to 680.4 kg•m/s. Then, she was given a huge bouquet which changed her total mass and speed. The thing we need to know is that the momentum before receiving the bouqet and after that are the same. With the bouqet, the mass increased and now is 63 kg + 4.4 kg = 67.4 kg. If p=m•v, then v=p/m, so her new speed is 680.4/67.4 = 10.0949, or approximately 10.1 m/s.

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A heavy meterstick has a mass of 1 kg. When the meterstick is thrown like a spear past you, you measure its momentum to be 2mv.
CaHeK987 [17]

Answer:

Its length is measured to be 0.5 m

Explanation:

From theory of relativity (mass variation), we know that:

m = mo/√(1-v²/c²)

Where, m = relative mass

and, mo = rest mass

The momentum of stick while moving, will be:

P = mv

but, it is given in the form of rest mass as:

P = 2(mo)v

thus, by comparison;

2(mo)v = mv

using value of m from theory of relativity;

2(mo)v = (mo)v/√(1-v²/c²)

√(1-v²/c²) = 1/2     ______ eqn(1)

Now, for relativistic length (L), we have the formula from same theory of relativity;

L = (Lo)√(1-v²/c²)

The rest length (Lo) of meter stick is 1 m, and the remaining term on right side √(1-v²/c²), known as Lorentz Factor, can be given by eqn (1), as equal to 1/2.

Thus,

L = (1 m)(1/2)

<u>L = 0.5 m</u>

4 0
3 years ago
A string, stretched between two fixed posts, forms standing-wave resonances at 325 Hz and 390 Hz. What is the largest possible v
Pavel [41]

Answer:

65

Explanation:

The resonant frequencies for a fixed string is given by the formula  nv/(2L).  

Where n is the multiple .

v is speed in m/s .

The difference between any two resonant frequencies is given by v/(2L)= fn+1 – fn

fundamental frequency means n=1

i.e  fn+1 – fn = 390 -325

                      =  65

3 0
3 years ago
the maximum intensity levels of a trumpet, trombone, and a bass drum, each at a distance of 3m are 94 dB, 107dB, and 113dB respe
Gwar [14]

Answer:

β = 114 db

Explanation:

The intensity of sound in decibles is

          β = 10 log \frac{I}{I_{o}}

in most cases Io is the hearing threshold 1 10-12 W / cm²

let's calculate the intensity of each instrument

            I / I₀ = 10 (β / 10)

            I = I₀ 10 (β / 10)

trumpet

            I1 = 1 10⁻¹² 10 (94/10)

            I1 = 2.51 10⁻³ / cm²

Thrombus

           I2 = 1 10⁻¹² 10 (107/10)

           I2 = 5.01 10-2 W / cm²

low

           I3 =1 1-12    (113/10) W/cm²

            I3 = 1,995 10-1 W / cm²

when we place the three instruments together their sounds reinforce

           I_total = I₁ + I₂ + I₃

           I_ttoal = 2.51 10-3 + 5.01 10-2 + ​​1.995 10-1

           I_total = 0.00251 + 0.0501 + 0.1995

           I_total = 0.25211 W / cm²

let's bring this amount to the SI system

         β = 10 log (0.25211 / 1 10⁻¹²)

           β = 114 db

7 0
3 years ago
The density of an object is dependent upon the object’s mass and ---
kotegsom [21]

Answer:Volume

Explanation:

Density = mass/ Volume

7 0
3 years ago
BRAINLIEST!!!!!
Serggg [28]

Answer:

A., an action which causes movement and an opposite reaction

Explanation:

I don't really know how to explain it, but this helped hopefully! :) Have a bless day

5 0
3 years ago
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