Ask question

Ask question

All categories

3 years ago

5

A high-speed flywheel in a motor is spinning at 500 rpm when a power failure suddenly occurs. The flywheel has mass 39.0 kg and

diameter 80.0 cm. The power is off for 32.0 s and during this time the flywheel slows due to friction in its axle bearings. During the time the power is off, the flywheel makes180 complete revolutions.
A. At what rate is the flywheel spinning when the power comes back on? (rad/s)

B. How long after the beginning of the power failure would it have taken the flywheel to stop if the power had not come back on? (s)

C. How many revolutions would the wheel have made during this time?

1 answer:

dimaraw [331]3 years ago

4 0

Answer:

a. 5.83 πrad/s

b. 49.03s

c. 408.67 πrad

Explanation:

You might be interested in

vA child is in danger of drowning in the Merimac river. The Merimac river has a current of 3.1 km/hr to the east. The child is 0

ikadub [295]

Answer:

$d = 2.26 km$

Explanation:

Let the child is moving with speed same as the speed of water flow

So here the position of child with respect to flow must be zero

And if the boat start at an angle with the vertical

so its relative speed with flow of water is given as

$v_x = 24.8 sin\theta$

$v_y = 24.8 cos\theta$

now the time to reach the child is given as

$\frac{0.6}{24.8 cos\theta} = \frac{2.5}{24.8 sin\theta }$

so now we have

$\theta = 76.5 degree$

So the time to catch the child is given as

$t = \frac{0.6}{24.8 cos78.2}$

$t = 0.104 h$

So distance moved by it in 0.104 h

distance moved by the boat in upstream direction given as

$x = (24.8 sin 74.8 - 3.1)(0.104)$

$x = 2.18 km$

In y direction the displacement of boat is

$y = 0.6 km$

net displacement of the ball is given as

$d = \sqrt{x^2 + y^2}$

$d = \sqrt{2.18^2 + 0.6^2}$

$d = 2.26 km$

4 0

3 years ago

A pulley system lifts a 1345 n weight a distance of 0.975m. Paul pulls the rope a distance of 3.90m, exerting a force of 375N. A

Rashid [163]

A. IMA: 4

The Ideal Mechanical Advantage (IMA) is given by:

$IMA = \frac{d_i}{d_o}$

where

$d_i$ is the input distance

$d_o$ is the output distance

For the pulley system in this problem, $d_i = 3.90 m$ and $d_o = 0.975 m$ , so the IMA is

$IMA=\frac{3.90 m}{0.975 m}=4$

B. MA: 3.59

The actual mechanical advantage (AMA), or simply the Mechanical Advantage (MA), is given by

$MA=\frac{F_o}{F_i}$

where $F_o$ is the output force and $F_i$ is the input force. For the pulley system in this problem, $F_i = 375 N$ and $F_o = 1345 N$ , so the MA is

$MA=\frac{1345 N}{375 N}=3.59$

C. Efficiency: 89.8 %

The efficiency of a machine is equal to the ratio between the MA and the AMA:

$\eta = \frac{MA}{AMA} \cdot 100$

Therefore, in this case,

$\eta=\frac{3.59}{4}\cdot 100=0.898=89.8 \%$

3 0

3 years ago

You've been tired and lethargy what are two possible reasons?

dybincka [34]

Explanation:

physical exertion.

lack of physical activity.

lack of sleep.

being overweight or obese.

periods of emotional stress.

boredom.

grief.

taking certain medications, such as antidepressants or sedatives.

5 0

3 years ago

what is the mechanical advantage of a crowbar when a worker uses 10N of force to pry open a window that has a resistance of 500N

Oksana_A [137]

Answer:

50

Explanation:

The mechanical advantage of a machine is given by

$MA=\frac{F_{out}}{F_{in}}$

where

$F_{out}$ is the output force

$F_{in}$ is the input force

For the crowbar in this problem,

$F_{in}=10 N$ is the force in input applied by the worker

$F_{out}=500 N$ is the force that the machine must apply in output to overcome the resistance of the window and to open it

Substituting into the equation, we find

$MA=\frac{500}{10}=50$

3 0

3 years ago

Read 2 more answers

What is the ability to complete extended periods of physical activity?

Galina-37 [17]

Answer:

D) WELLNESS

Explanation:

3 0

2 years ago

Read 2 more answers