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3 years ago

I would appreciate some help.

1 answer:

4 0

You oughtta be able to do this one.

The "efficiency" is just the portion of the input work that
comes out in a useful form.

If the efficiency is 70%, that tells you that however much work
you put INto the machine, the machine will do 70% of that much
work for you at the output side.

Put 20,000 J in ... out comes (0.70) x (20,000 J) = 14,000 J .

What happens to the other 30% of the work you put into it ?
It turns into HEAT. That's why machines always have to be
cooled somehow while they're running.

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What are the positive impacts of Genetically Modified Crops?

xeze [42]

Answer:

The crops will have the ability to be resistant to certain diseases

7 0

2 years ago

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A 60-watt light bulb has a voltage of 120 bolts applied across it and a current of 0.5 amperes flows through the bulb. What is t

Andre45 [30]

Answer:

240 ohms

Explanation:

From Ohms law we deduce that V=IR and making R the subject of the formula then R=V/I where R is resistance, I is current and V is coltage across. Substituting 120 V for V and 0.5 A for A then

R=120/0.5=240 Ohms

Alternatively, resistance is equal to voltage squared divided by watts hence $\frac {120^{2}}{60}=240$

7 0

3 years ago

Place the following into scientific notation...(.000635) *

AleksAgata [21]

6.35x10^-4 OR 6.3x10-4 (if only one decimal number is allowed)

6 0

3 years ago

A cord is attached to the box and run through a pulley directly above the box, so that the cord is vertical. The free end of the

Harman [31]

Answer:

The answer is given here would be a simplified equation, seeing as there are some missing variables in the question.

F1 = T- 46, 674.656 gm/s²

Explanation:

Note: Once we have the mass of the second object and/or acceleration of the cord, we can solve for the force of the ground acting on the box.

To calculate the force caused by gravity on the basic pulley system we use the following equation:

F2 = M2 x g; where g= gravitational acceleration (a constant equal to 9.8 m/s²). The mass M2 = 10.5 lb = 4762.72g

∴ F2 = 4762.72g x 9.8 m/s²

= 46, 674.656 gm/s² or 46, 674.656 N

But since this F2 is acting in a downlowrd direction, it would be negative.

Tension of the cord, T = Mass, x × acceleration. ( x is in the pulley diagram)

⇒ F1 = T - F2

F1 = T- 46, 674.656 gm/s²

4 0

3 years ago

A circular loop of wire with radius r=0.0250 m and resistance r=0.390 ohms is in a region of spatially uniform magnetic field. t

slavikrds [6]

Answer:

0.0133 A

Explanation:

The time at which B=1.33 T is given by

1.33 = 0.38*t^3

t = (1.33/0.38)^(1/3) = 1.52 s

Using Faraday's Law, we have

emf = - dΦ/dt = - A dB/dt = - A d/dt ( 0.380 t^3 )

Area A = pi * r² = 3.141 *(0.025 *0.025) = 0.00196 m²

emf = - A*(3*0.38)*t^2

thus, the emf at t=1.52 s is

emf = - 0.00196*(3*0.38)*(1.52)^2 = -0.0052 V

if the resistance is 0.390 ohms, then the current is given by

I = V/R = 0.0052/0.390 = 0.0133 A

3 0

3 years ago