Ask question

Ask question

All categories

3 years ago

7

Sarah moves her box in 3 minutes and does 14 J of work. John moves his box in the same amount of time using 12 J of work. Who is

more powerful?

2 answers:

Mekhanik [1.2K]3 years ago

4 0

(Energy) divided by (time) = (power). / / / / / / (More energy) divided by (same time) = (more power).

Vikentia [17]3 years ago

4 0

Just took the test, the answer was "Sarah, since she moved her box in the same amount of time but did more work."

You might be interested in

lisabon 2012 [21]

Sustainable buildings are generally less expensive over the lifetime of the building, due to lower energy costs in production of the materials and lower energy bills. Option A is correct.

<h3>What is sustainable buildings? </h3>

Sustainable buildings refer to both a structure and the implementation of environmentally responsible and resource-efficient methods.

Sustainable buildings are generally less expensive over the lifetime of the building, due to lower energy costs in production of the materials and lower energy bills,

Hence,option A is correct.

To learn more about the sustainable buildings, refer;

brainly.com/question/8434592

#SPJ1

5 0

2 years ago

A vacuum gage connected to a chamber reads 39 kPa at a location where the atmospheric pressure is 92 kPa. Determine the absolute

Nata [24]

Answer: 53 kPa

Explanation:

Absolute pressure is a pressure value referred to absolute zero or vacuum. This value indicates the total pressure to which a body or system (the chamber in this situation) is subjected, considering the total pressure acting on it.

In this sense, the equation that will be useful in this case is:

$P_{atmospheric}= P_{absolute} + P_{vacuum}$ (1)

Where:

$P_{atmospheric}=92 kPa$ is the atmospheric pressure

$P_{vacuum}=39 kPa$ is the vacuum pressure

$P_{absolute}$ is the absolute pressure

Isolating $P_{absolute}$ from (1):

$P_{absolute}=P_{atmospheric} - P_{vacuum}$ (2)

$P_{absolute}=92 kPa - 39 kPa$ (3)

Finally:

$P_{absolute}=53 kPa=53(10)^{3} Pa$ This is the absolute pressure in the chamber

7 0

4 years ago

A rock is dropped (from rest) off a bridge over the Merrimack River. The falling rock

rewona [7]

Answer:

31.25 meters or ~31 meters approximately

Explanation:

Let's see which of the 5 variables we are given since this is a constant acceleration problem.

$v_i \ \ \ \ \ \ t \\ v_f \ \ \ \ \ \triangle x \\ a$

We want to find the height of the bridge, aka the vertical displacement of the rock. Let's set the upwards direction to be positive and the downwards direction to be negative.

We are told that the acceleration is 10 m/s² downward, so we have a = -10 m/s².

We are also told that the time it takes the rock to hit the water is 2.5 seconds. Time is the same regardless of the x- or y- direction, so we can say that t = 2.5 seconds.

Now, we aren't told this directly, but we can figure out that the velocity in the y-direction is 0 m/s, since the rock is dropped from rest off the bridge. Therefore, $v_i=0 \frac{m}{s}$ .

We want to find the vertical displacement, the height of the bridge, so we can say that $\triangle x= \ ?$

We have 4 out of 5 variables:

$v_i,\ a, \ t, \ \triangle x$

Look through the constant acceleration equations to see which equation has all 4 of these variables. You should come up with this one (no final velocity):

$x_f=x_i+v_it+\frac{1}{2}at^2$

Subtract $x_i$ from both sides of the equation to get:

$\triangle x=v_it+\frac{1}{2}at^2$

Substitute in our known variables and solve for delta x.

$\triangle x=(0\frac{m}{s})(2.5s) + \frac{1}{2} (-10\frac{m}{s^2})(2.5s)^2$

0 m/s multiplied by 2.5 s is 0, so we have:

$\triangle x =\frac{1}{2} (-10)(2.5)^2$

Evaluate the exponent first and multiply the terms together.

$\triangle x =(-5)(6.25)$
$\triangle x =-31.25$

The vertical displacement is -31.25 meters from the rock's starting position, so we can say that the height of the bridge is 31.25 meters, which is approximately 31 meters tall.

7 0

3 years ago

Read 2 more answers

What is meant by a charge carrier hole in a semiconductor? Can it be created in a conductor?

lara [203]

Answer:

The materials used to make electronic components like transistor and integrated, circuit behave as if effective particles known as electron through them, causing electrical properties

6 0

4 years ago

Am radio signals have frequencies between 550 khz and 1600 khz (kilohertz) and travel with a speed of 3.00 ✕ 108 m/s. what are t

Allisa [31]

The minimum frequency is
$f_1 = 550 kHz = 5.50 \cdot 10^5 Hz$
while the maximum frequency is
$f_2 = 1600 kHz = 1.6 \cdot 10^6 Hz$
Using the relationship between frequency f of a wave, wavelength $\lambda$ and the speed of the wave v, we can find what wavelength these frequencies correspond to:
$\lambda_1 = \frac{v}{f_1}= \frac{3 \cdot 10^8 m/s}{5.5 \cdot 10^5 Hz}=545 m$
$\lambda_2 = \frac{v}{f_2}= \frac{3 \cdot 10^8 m/s}{1.6 \cdot 10^6 Hz}=188 m$

So, the wavelengths of the radio waves of the problem are within the range 188-545 m.

5 0

3 years ago