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2 years ago

6

How does an air mattress protect a stunt person landing on the ground after a stunt?

1 answer:

Fudgin [204]2 years ago

6 0

Answer:

a) It reduces the kinetic energy loss of the stunt person.

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Bats are extremely adept at catching insects in midair. If a 81.5-g bat flying in one direction at 7.21 m/s catches a 8.11-g ins

aivan3 [116]

You can look that up on google

7 0

2 years ago

shepuryov [24]

Answer:

a) I = 464 kg m², b) K = 631 .6 J, c) v = 8.25 m / s

Explanation:

a) the moment of inertia of point particles is

I = ∑ m_i r_i²

in this case

I = 8 5² + 3 (-2) ² + 7 (-6) ²

I = 464 kg m²

b) The kinetic energy is

K = ½ I w²

K = ½ 464 1.65²

K = 631 .6 J

c) linear and angular velocity are related

v = w r

v = 1.65 5

v = 8.25 m / s

8 0

2 years ago

A 40-cmcm-long tube has a 40-cmcm-long insert that can be pulled in and out. A vibrating tuning fork is held next to the tube. A

Licemer1 [7]

Answer:

1070 Hz

Explanation:

First, I should point out there might be a typo in the question or the question has inconsistent values. If the tube is 40 cm long, standing waves cannot be produced at 42.5 cm and 58.5 cm lengths. I assume the length is more than the value in the question then. Under this assumption, we proceed as below:

The insert in the tube creates a closed pipe with one end open and the other closed. For a closed pipe, the difference between successive resonances is a half wavelength $\frac{\lambda}{2}$ .

Hence, we have

$\dfrac{\lambda}{2}=58.5-42.5=16 \text{ cm}$

$\lambda=32\text{ cm}=0.32 \text{ m}$ .

The speed of a wave is the product of its wavelength and its frequency.

$v=f\lambda$

$f=\dfrac{v}{\lambda}$

$f=\dfrac{343}{0.32}=1070 \text{ Hz}$

7 0

3 years ago

A 5000 kg African elephant has a resting metabolic rate of 2500 W. On a hot day, the elephant's environment is likely to be near

alina1380 [7]

Answer:

36 kg

Explanation:

To answer this question, a few assumptions have to be made:

That the temperature on the day is 35 °C
That all the heat from the elephant is goes to warming/evaporating the water on the surface of the elephant

Energy released per hour = 2500 J/s * 3600 s = 9 000 000 J

Q = mcΔT

9 000 000 J= m *4.186 J/g-K * (373K - 308K) + m*2260 J/g

m = 36 000 g = 36 kg

3 0

3 years ago

Q.By the method of dimensional analysis derive the

Artyom0805 [142]

Answer

a) Using dimensional analysis we cannot derive the relation, But we can check the correctness of the formula.

$s = u t +\dfrac{1}{2}at^2$

now, L H S

s = distance

dimension of distance = [M⁰L¹T⁰]

now, equation on the right hand side

R H S

u = speed

u = m/s

Dimension of speed = [M⁰L¹T⁻¹]

dimension of time

t = sec

Dimension of time = [M⁰L⁰T¹]

Dimension of 'ut' = [M⁰L¹T⁻¹][M⁰L⁰T¹]

= [M⁰L¹T⁰]

now, acceleration= a

a = m /s²

dimension of acceleration = [M⁰L¹T⁻²]

dimension of (at²) = [M⁰L¹T⁻²][M⁰L⁰T¹][M⁰L⁰T¹]

= [M⁰L¹T⁰]

hence, the dimension are balanced.

so, L H S = R H S

b) Moment of inertia of hollow sphere = $\dfrac{2}{3}Mr^2$

Moment of inertia of solid sphere = $\dfrac{2}{5}Mr^2$

we know,

$\tau = I \alpha$

$\alpha=\dfrac{\tau}{I}$

Torque is the force that causes rotation

If the same amount of torque is applied to both spheres the sphere with bigger moment of inertia would have smaller angular velocity.

Thus the solid sphere would accelerate more.

4 0

3 years ago

Read 2 more answers