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3 years ago

12

Ruby was training for a race at the high school track. She took her dog walked 2250 meters in 15 minutes. Calculate the average

speed

1 answer:

Sedbober [7]3 years ago

4 0

Answer:

Average speed $= 2.5$ meter per second

Explanation:

Given

The total distance walked $= 2250$ meters

The total time taken to walk $2250$ meters is $15$ minutes

In one minute there are $60$ seconds

As we know Average speed is equal to total distance travelled divided by total time taken

Hence,

Average speed

$\frac{2250}{15*60} \\2.5$ meter per second

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A turbine blade rotates with angular velocity ω(t) = 2.00 rad/s- 2.1.00 rad/s3 t2. What is the angular acceleration of the blade

STatiana [176]

Answer:

$\alpha =-38.22\ rad/s^2$

Explanation:

given,

ω(t) = 2.00 rad/s- 2.1.00 rad/s³ t²

angular acceleration of the blade at t= 9.10 s

$\alpha =\dfrac{d\omega}{dt}$

$\alpha =\dfrac{d}{dt}(2 - 2.1 t^2)$

$\alpha =-2 \times 2.1 t$

$\alpha =-4.2 t$

angular acceleration of blade at t = 9.10

$\alpha =-4.2\times 9.10$

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3 years ago

What is the biological impact of minimum catch sizes on a population of fish?

ivann1987 [24]

The population comes to be dominated by smaller, slower-growing individuals

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4 years ago

When testing a laptop power connector, how close should the voltage measured be to the accepted voltage of the laptop?

elixir [45]

When testing a laptop power connector, the voltage measured has be close to +/- 5% to the accepted voltage of the laptop. This is to ensure that the power connector would not pose any hazard to the user and is safe for use. So, for instance the accepted voltage is 19 V, when you test the power connector it should be that the reading is between 18 V to 20 V. Any reading below or above that range is not recommended for use. You can locate the accepted voltage on the battery or the laptop itself. To test a power connector, you can use a volt meter or a multi meter.

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4 years ago

A small block of mass M = 0.10 kg is released from rest at point 1 at a height H = 1.8 m above the bottom of a track, as shown i

Ede4ka [16]

Answer:

D

Explanation:

A) is not correct, because the gravitation potential energy will depend on the height the block is located at. It will be calculated with the formula:

U=mgh.

If we take the ground as a zero height reference, then on point 2 the potential energy will be:

$U_{2} = 0.10kg(9.81 m/s^{2})(0.6m)$

$U_{2}=0.59 J$

While on point 3, the potential energy will be greater.

$U_{3}=0.10kg(9.81 m/s^{2})(1.2m)$

$U_{3}=1.18 J$

B) is not the right answer because the kinetic energy will vary with the height the block is located at in the fact that the energy is conserved (this is if we don't take friction into account or air resistance) so in this case:

$U_{2}+K_{2}= U_{3}+K_{3}$

We already know the potential energy at point 2. We can calculate the kinetic energy at point 3 like this:

$K_{3} =\frac{1}{2}mv_{3}^{2}$

$K_{3} =\frac{1}{2}(0.10kg)(2.5 m/s)^{2}$

$K_{3} =0.31 J$

So the kinetic energy at point 2 is given by the equation:

$K_{2} =U_{3}-U_{2}+K_{3}$

so:

$K_{2} = (1.18J)-(0.59J)+0.31J$

$K_{2} =0.9J$

As you may see the kinetic energy at point 2 is greater than the kinetic energy at point 3.

C) Is not correct because according to the first law of thermodinamics, energy is not lost, only transformed. So, since we are not taking into account friction or any other kind of loss, then we can say that the amount of mechanical energy at point 1 is exactly the same as the mechanical energy at point 3.

D) Because of what we talked about on part C, this will be the true situation, because the mechanical energy of the block will be the same no matter theh point you measure it at.

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3 years ago

What is the mass of a rock lifted 2 meters off the ground that has 196 J of potential energy?

eimsori [14]

Answer:

10kg

Explanation:

Let PE=potential energy

PE=196J

g(gravitational force)=9.8m/s^2

h(change in height)=2m

m=?

PE=m*g*(change in h)

196=m*9.8*2

m=10kg

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3 years ago