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3 years ago

A machine is brought in to accomplish a task which requires 100 ft.-lbs. of work. Which statements are correct:

1 answer:

7 0

Answer: The two answers are the machine will require an input greater than 100 ft.-lbs. And the other is The machine may accomplish the task faster than manual work.

Hope this help :3

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!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Korvikt [17]

Answer:

Second choice

Explanation:

I suppose ME is the same as POTENTIAL energy

ME = mgh = 70 * 10 * 12 = 8400j

Half way down, 4200 j is converted to Kinetic Energy

1/2 m v^2 = 4200

1/2 (70) v^2 = 4200 v = 10.95 m/s

Just before impact ALL of the 8400 j is now KE
1/2 (70)v^2 = 8400 v = 15.49 m/s

4 0

2 years ago

A penny dropped into a wishing well reaches the bottom in 2.50 seconds. What was the velocity at impact?

12345 [234]

Answer:

Taking it was dropped with inital velocity of 0m/s.

v = u+at

v = 0 + 9.8*1.5

v = 14.7s

(a=9.8m/s^2 << That's the acceleration due to gravity)

Explanation:

4 0

3 years ago

Read 2 more answers

Megan wants to see if mice that are fed food A or B grow at a faster rate. She measures the mass of the mice on day 1, then divi

diamong [38]

<span>No, there is no control group because each group is treated under test conditions.</span>

7 0

3 years ago

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A ladder 10 ft long rests against a vertical wall. If the bottom of the ladder slides away from the wall at a rate of 1.4 ft/s,

Art [367]

Answer:

$\dfrac{d\theta}{dt} =-0.233\ rad/s$

Explanation:

given,

length of ladder = 10 ft

let x be the distance of the bottom and y be the distance of the top of ladder.

x² + y² = 100

differentiating with respect to time we get

$2 x\dfrac{dx}{dt}+2y\dfrac{dy}{dt} = 0$ ..............(1)

when x = 8 and y = 6 and when \dfrac{dx}{dt} = 1.4ft/s

from equation (1)

now,

$16\times 1.4 + 12\dfrac{dy}{dt} = 0$

$\dfrac{dy}{dt} = -\dfrac{5.6}{3}$

let the angle between the ladders be θ

$tan\theta = \dfrac{y}{x}$

y = xtan θ

$\dfrac{dy}{dt} =\dfrac{dy}{dt} tan\theta + x sec^2\theta\dfrac{d\theta}{dt}$

$-\dfrac{5.6}{3} =1.4\times \dfrac{6}{8} + 8 (1+\dfrac{9}{16})\dfrac{d\theta}{dt}$

$\dfrac{25}{2} \dfrac{d\theta}{dt} =\dfrac{-17.5}{6}$

$\dfrac{d\theta}{dt} =-0.233\ rad/s$

6 0

3 years ago

A pushing force acts on a toy car for 3 seconds causing it to accelerate at a rate A’. If the car is replaced with a similar, bu

Alla [95]

Answer:

one-half of A'

Explanation:

3 0

3 years ago

Read 2 more answers