What two forces act on falling bodies?

A yo-yo is made from two uniform disks, each with mass m and radius R, connected by a light axle of radius b. A light, thin stri

schepotkina [342]

Answer:

linear acceleration

$a = \frac{2g}{2 + \frac{R}{b}}$

angular acceleration

$\alpha = \frac{2g}{R(2 + \frac{R}{b})}$

Explanation:

As we know that the force due to tension force is upwards while weight of the disc is downwards

so we will have

$2mg - T = 2ma$

also we have

$Tb = (\frac{1}{2}mR^2 + \frac{1}{2}mR^2)\alpha$

now we have

$Tb = mR^2(\frac{a}{R})$

$T = \frac{mRa}{b}$

now we have

$2mg = (2ma + \frac{mRa}{b})$

$a(2 + \frac{R}{b}) = 2g$

so we have

linear acceleration

$a = \frac{2g}{2 + \frac{R}{b}}$

angular acceleration

$\alpha = \frac{2g}{R(2 + \frac{R}{b})}$

4 0

3 years ago

Sam's job at the amusement park is to slow down and bring to a stop the boats in the log ride. You may want to review ( pages 29

hjlf

The work that Sam should do in order to stop is the boat is the same as that of the kinetic energy of the object in order to counter its motion. Kinetic energy is calculated through the equation,
KE = 0.5mv²
where KE is kinetic energy, m is mass, and v is the velocity.
Substituting,
KE = 0.5(1200kg)(1.2 m/s)²
KE = 864 J

5 0

4 years ago

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The threshold of hearing is defined as the minimum discernible intensity of the sound. It is approximately 10âˆ’12w/m2. Find the

Monica [59]

Answer:

The distance d from the car at which the sound from the stereo can still be discerned = 97720.5 m

Explanation:

Sound intensity heard at distance is related to the distance with the relation = (power of sound at the source)/(surface area of the wall of an imaginary sphere at the distance in question)

I = P/4πd²

Assuming the car has 2 speakers,

P = 0.06 W × 2 = 0.12 W

d = ?

For the intensity of the least discernible sound,

I = 10⁻¹² W/m²

10⁻¹² = 0.12/4πd²

d = 97720.5 m

8 0

3 years ago

Please help!!!!!!!! 25 points

Archy [21]

Answer:

B: beaks, finches.

Explanation:

Beaks, finches. This is because he noticed that fruit-eating finches had beaks similar to parrots, while finches that ate insects had narrow beaks. The difference in their beaks is due to adapting to different environments which causes them to evolve into different species of finches.

7 0

3 years ago

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How much force would be needed to

Galina-37 [17]

There would be two forces acting on the box parallel to the floor, with a net force of

∑ F = p - f = m a

where p = magnitude of the push, f = mag. of friction, m = mass of the box, and a = acceleration. To find p, we first need f .

There are also only two forces acting on the box perpendicular to the floor, with net force

∑ F = n - w = 0

where n = mag. of normal force of the floor on the box and w = weight of the box. The net force is 0 because the box is only accelerating parallel to the floor.

w = m g, where g = 9.8 m/s² is the mag. of the acceleration due to gravity, so we can solve for n :

n = w = m g

n = (22 kg) (9.8 m/s²)

n = 215.6 N

The kinetic friction is proportional to the normal force by a factor of the given coefficient of friction, µ = 0.17, such that

f = µ n

f = 0.17 (215.6 N)

f = 36.652 N

Now solve for the required pushing force:

p - 36.652 N = (22 kg) (1.9 m/s²)

p ≈ 78 N

4 0

4 years ago

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