In complete sentences describe the motion of the block and the scooter throughout this activity ?

A vinyl record is played by rotating the record so that an approximately circular groove in the vinyl slides under a stylus. Bum

Fed [463]

Answer:

983.400345675 hits per second

Explanation:

Radius = 14.2 cm

Record turn rate = 33 rev/min

Bump separation = 0.499 mm

Circumference of the record = $2\pi 0.142=0.89221231362\ m$

Number of bumps in the groove = $\dfrac{0.89221231362}{0.499\times 10^{-3}}=1788.0006285\ bumps$

The rate which the bumps hit the stylus = $33\times\dfrac{1788.0006285}{60}=983.400345675$

The rate at which the bumps hit the stylus 983.400345675 hits per second

8 0

3 years ago

A bus is designed to draw its power from a rotating flywheel that is brought up to 3000 rpm by an electric motor. The flywheel i

Arada [10]

To solve this problem we will apply the concept of rotational kinetic energy. Once this energy is found we will proceed to find the time from the definition of the power, which indicates the change of energy over time. Let's start with the kinetic energy of the rotating flywheel is

$E_r = \frac{1}{2} I\omega^2$

Here

I = moment of inertia

$\omega =$ Angular velocity

Here we have that,

$\omega = 3000\frac{rev}{min}(\frac{2\pi rad}{1rev})(\frac{1min}{60s})$

$\omega = 314.159rad/s$

Replacing the value of the moment of inertia for this object we have,

$E_r = \frac{1}{2} (\frac{MR^2}{2})\omega^2$

$E_r = \frac{1}{2} (\frac{2000(0.5)^2}{2})(314.159)^2$

$E_r = 1.233698*10^7J$

The expression for average power is

$P = \frac{E_r}{\Delta t}$

$\Delta t = \frac{E_r}{P}$

$\Delta t = \frac{1.233698*10^7}{20*10^3}$

$\Delta t = 616.8s \approx 620s$

Therefore the correct answer is 620s.

3 0

4 years ago

To drive a typical car at 40 mph on a level road for one hour requires about 3.2 × 107 J of energy. Suppose we tried to store th

tatiyna

Answer:

9000RPM

Explanation:

"Angular velocity" is directly related to kinetic energy, that is, the Kinetic energy equation would allow an approximation to the resolution investigated in the problem.

The equation for KE is given by:

$KE = \frac{1}{2} lw ^ 2$

Now, starting from there towards the <em>Angular equation of kinetic energy</em>, the moment of inertia (i) is used instead of mass (m), and angular velocity (w) instead of linear velocity (V)

That's how we get

$KE_{Angular} = \frac{1}{2} Iw^2$

calculating the inertia for a solid cylindrical disk, of

m = 400kg

r = 1.2 / 2 = 0.6m

$I_{disk} = \frac{1}{2} mr^2 = (0.5) (400) (0.6)^2 = 72 kgm^2$

We understand that the total kinetic energy is 3.2 * 10 ^ 7J, like this:

$3.2*10^7 = \frac{1}{2} Iw^2 = (0.5) (72) w^2 = 36w^2$ $w^2 = 3.2*10^7 / 36 = 0.0888*10^7 = 88.8*10^4$

$w = 9.43*10^2 = 943 rad / s$

Thus,

943 rad / s ≈ 9000 rpm

6 0

3 years ago

An astronaut is moving in space when a big explosion occurs about 50 meters behind him. How will the astronaut come to know abou

LUCKY_DIMON [66]

Answer:

The correct answer is B.

The astronaut will know due to the light from the explosion.

Explanation:

Sound and vibrations require a medium such as air to travel through. Space, there is no air. Only a vacuum. So sound and vibrations are unable to travel. Light requires no medium to travel. It can go through a vacuum.

Therefore the Astronaut will see a bright flash of light as it travels from the explosion to outer space. It is also important to note that light can travel very far because nothing else interacts with its wave particles and as such, it cannot be impeded.

Cheers!

7 0

3 years ago

What is true about mass and volume of all sinking objects

katrin [286]

That have a high mass and low volume I think

3 0

3 years ago