The effiency of a machine is

(output work or energy) / (input work or energy) .

For the system described in the question, that's

(123 J) / (150 J) = 0.82 = 82% .

4 0

3 years ago

(m = 4.0 kg) the cockroach rides on the rim (at radius R) of a disk (M = 6.0 kg) that turns about its center like a merry-go-rou

kvasek [131]

Answer:

ω' = 2.5 rad/s

Explanation:

mass of cockroach, m = 4 kg

mass of disk, M = 6 kg

Radius of disc= R

initial angular velocity, ω = 2 rad/s

Let the final angular velocity is ω'

As no external torque is applied, so the angular momentum is constant.

Angular momentum = Moment of inertia x angular velocity

I ω = I' ω'

$\frac{1}{2}\left ( M+m \right )R^{2}\times {2} = \left (\frac{1}{2}MR^{2}+m(0.5R)^{2}) \right )\omega '$

$10R^{2} = 4R^{2}\omega '$

ω' = 2.5 rad/s

5 0

4 years ago

PEDALING A BIKE : ACCELERATION:: PULLING A DOGS LEASH: _____.

Alex_Xolod [135]

Pulling a dogs leash: inertia

6 0

4 years ago

As a science project, you drop a watermelon off the top of the Empire State Building, 320 m above the sidewalk. It so happens th

MA_775_DIABLO [31]

Answer:

Watermelon is going at a speed of $13.33\ \rm m/s$ in downward direction

Explanation:

Given

Height of the Empire State building = 320 m
Speed of the superman = 24 m/s

since both the motion of both watermelon and the superman is under gravity. The acceleration of both is g in downwards direction. So the relative acceleration between them is zero and when they meet the relative distance covered by them will be the height of the Empire State building.

so let t be the time when they meet given by

$\dfrac{320}{24}\\t=13.33\ \rm s$

Now let v be the velocity of the the watermelon when they meet given by

$v=gt\\v=9.8\times13.33\\v=130.63\ \rm m/s$

6 0

3 years ago

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Easiest way to Find fahrenhiet to celsius please i need necessary 20 for the fastest correct answer​

Easiest way to Find fahrenhiet to celsius please i need necessary 20 for the fastest correct answer