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s344n2d4d5 [400]

3 years ago

5

You wish to lift a 12,000 lb stone by a vertical distance of 15 ft. Unfortunately, you can only generate a maximum pushing force

of 2,000 lb. What is the amount of work you must input in order to move the stone

1 answer:

DochEvi [55]3 years ago

6 0

Answer:

5,760,000 lb-ft²/s²

Explanation:

Work done, W = mgy where m = mass of stone = 12,000 lb, g = 32 ft/s² and y = vertical distance = 15 ft.

So, W = mgy = 12,000 lb × 32 ft/s² × 15 ft. = 5,760,000 lb-ft²/s²

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f the CD rotates clockwise at 500 rpmrpm (revolutions per minute) while the last song is playing, and then spins down to zero an

vazorg [7]

Answer:

The magnitude of the angular acceleration is $a = 20.14 rad/s^2$

Explanation:

From the question we are told that

The angular speed of CD is $w_{CD} = 500 rpm = \frac{500 rpm}{\frac{60 \ s }{1 \ min} } * \frac{2 \pi }{ 1 \ rev} = 52.37 rad/s$

time taken to decelerate is $t_{CD} = 2.60\ s$

The final angular speed is $w_f= 0 \ rad/s$

The angular acceleration is mathematically represented as

$a = \frac{w_f - w_{CD}}{t}$

substituting values

$a = \frac{0 - 52.37}{2.60}$

$a = - 20.14 rad/s^2$

The negative sign show that the CD is decelerating but the magnitude is

$a = 20.14 rad/s^2$

3 0

3 years ago

Guys help...A spring that obeys Hooke's law, with a spring constant k1, is cut into N identical springs, each with a spring cons

Tems11 [23]

Answer:

K2 = N*K1

Explanation:

The force you apply to each section is the same you apply to the whole spring, but the extension of each section is dX/N (if dX is the extension of the entire spring)

4 0

3 years ago

Which of the following is a TRUE statement?

pshichka [43]

Answer:

e. All of these statements are false.

Explanation:

As we know that heat transfer take place from high temperature to low temperature.

It is possible to convert all work into heat but it is not possible to convert all heat in to work some heat will be reject to the surrounding.

The first law of thermodynamics is the energy conservation law.

Second law of thermodynamics states that it is impossible to construct a device which convert all energy into work without rejecting the heat to the surrounding.

By using heat pump ,heat can transfer from cooler body to the hotter body.

Therefore all the answer is False.

5 0

3 years ago

A seagull flies at a velocity of 9.00 m/s straight into the wind. (a) if it takes the bird 20.0 min to travel 6.00 km relative t

enot [183]

Here we will the speed of seagull which is v = 9 m/s

this is the speed of seagull when there is no effect of wind on it

now in part a)

if effect of wind is in opposite direction then it travels 6 km in 20 min

so the average speed is given by the ratio of total distance and total time

$v_{avg} = \frac{6000}{20*60}$

$v_{avg} = 5m/s$

now since effect of wind is in opposite direction then we can say

$V_{net} = v_{bird} - v_{wind}$

$5 = 9 - v_{wind}$

$v_{wind}= 4 m/s$

Part b)

now if bird travels in the same direction of wind then we will have

$v_{net}= v_{bird} + v_{wind}$

$v_{net} = 9 + 4 = 13 m/s$

now we can find the time to go back

$time = \frac{distance}{speed}$

$time = \frac{6000}{13}$

$time = 7.7 minutes$

Part c)

Total time of round trip when wind is present

$T = t_1 + t_2$

$T = 20 + 7.7 = 27.7 min$

now when there is no wind total time is given by

$T = \frac{6000}{9} + \frac{6000}{9}$

$T = 22.22 min$

So due to wind time will be more

4 0

4 years ago

If a car is moving backward and has negative acceleration, what can be said about the speed of the car?

KATRIN_1 [288]

I think its A let me know its wrong or not

4 0

3 years ago

Read 2 more answers