Which of the following instrument measure time most accurately

A uniform-density 7 kg disk of radius 0.21 m is mounted on a nearly frictionless axle. Initially it is not spinning. A string is

GREYUIT [131]

Answer:

$\omega = 22.67 rad/s$

Explanation:

Here we can use energy conservation

As per energy conservation conditions we know that work done by external source is converted into kinetic energy of the disc

Now we have

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

now we know that work done is product of force and displacement

so here we have

$W = F.d$

$W = (44 N)(0.9 m) = 39.6 J$

now for moment of inertia of the disc we will have

$I = \frac{1}{2}mR^2$

$I = \frac{1}{2}(7 kg)(0.21^2)$

$I = 0.154 kg m^2$

now from above equation we will have

$39.6 = \frac{1}{2}(0.154)\omega^2$

$\omega = 22.67 rad/s$

5 0

3 years ago

Read 2 more answers

How much tension must a rope withstand if it is used to accelerate a 6526 kg car vertically upwards at 8.9 m/s^2?

ExtremeBDS [4]

Answer:

The value is $T = 122036.2 \ N$

Explanation:

From the question we are told that

The mass of the car is $m = 6526 \ kg$

The acceleration is $a= 8.9 \ m/s^2$

Generally the net force applied on the rope is mathematically represented as

$F_{net} = T - W$

Here W is the weight of the car which is evaluated as

$W = m * g$

=> $W = 6526 * 9.8$

=> $W = 63954.8 \ N$

Generally the net force can also be mathematically represented as

$F = m * a$

So

$m * a = T - 63954.8$

=> $6526 * 8.9 = T - 63954.8$

=> $T = 122036.2 \ N$

7 0

3 years ago

When the mirror is rotated, the normal will turn as well, but will the incident Ray and reflected ray turn?

Inessa [10]

When a mirror is rotated . . .

-- The incident ray doesn't turn. It's just the line from the source to the mirror.
It would be there, in the same place, even if there was no mirror.

-- The normal turns. It's the line perpendicular to the mirror, so it must turn
with the mirror.

-- Since the normal tuns and the incident ray doesn't, the angle between them
must change. And since the angle of the reflected ray is equal to the angle of
the incident ray, the reflected ray must also turn.

6 0

3 years ago

On which variable does magnetic flux depend?A) the magnetic fieldB)the orientation of the field with respect to the region throu

hram777 [196]

Answer:

D) All of these

Explanation:

The magnetic flux through a coil of wire is given by:

$\Phi = BA cos \theta$

where

B is the intensity of the magnetic field

A is the area enclosed by the coil

$\theta$ is the angle between the direction of B and the normal to the area of the coil

Therefore, we see that the magnetic flux depends on all these quantities:

A) the magnetic field

B)the orientation of the field with respect to the region through which it passes

C)the area of a region through which magnetic field passes

So, the correct answer is

D) All of these

4 0

3 years ago

John and Leah want to move the piano in their living room. John pushes from behind the piano with a force of 300\text{ N}300 N30

Schach [20]

Answer:

1.3 m/s

Explanation:

(300N of Fa + 100N' of Fa) - 140N of Ff /200Kg

400N of Fa - 140N* of Ff

260 of ∑F/ 200kg = acceleration

a of piano = 1.3 m/s²

7 0

3 years ago