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2 years ago

Which of the following is correct for speed?

Physics

1 answer:

Olin [163]2 years ago

4 0

Answer:

Speed is a "scalar" quantity

(C) is the correct answer

An object could travel at 10 m/s to some point and then return to the origin at 10 m/s for an average speed of 10 m/s, however it's displacement over that time would be zero for a net velocity of zero.

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How can athletes promote social justice?

CaHeK987 [17]

ORLANDO, Fla. —

The NBA playoffs will pick up again this weekend after players made a powerful statement on Wednesday.

Athletes have a voice when it comes to change and demands for social justice. Their impact is extending off the court and into the world.

"We stand with them, we support them and we're there for them," Michael-Carter Williams said.

The Orlando Magic's Michael Carter-Williams spoke Thursday about the Milwaukee Bucks' decision not to play Wednesday and instead, making a demand for the end to social injustice.

"We have a big platform that we can use to really make change in this country and we can go home to our communities and make change there," Carter-Williams said.

The Bucks' decision led to all NBA games being postponed Wednesday, some baseball games weren't played, as well as soccer, and the WNBA.

"This was a historic moment last night, we never had anything like that happen before," Dr. Richard Lapchick said.

Lapchick is a UCF professor who is also the president of the Institute for Sport and Social Justice.

He says the impact from Wednesday's boycott can't be overstated.

"The unity that occurred between the players and teams and leagues, was particularly impressive," Lapchick said. "The importance of what the players are doing, and what the country is doing in response, is looking at more than police brutality, it's looking at systemic racism."

"People are just tired of what's going on, there's no justice at all," Sandy Lallavee said.

Lallavee is one of the many residents we spoke to who supports the athletes' desire for a committed dialogue and effective change.

"I think it's the right thing to do right now, I support their decision and I think it's terrible what's happening in the world, in America," Gerrod Trytten said.

"It's a younger generation doing things and trying to make change, I respect them and I think they're doing the right thing," Nick Trapp said.

"They're showing their humanity, they're showing what they really care about in society," Lapchick said.

6 0

2 years ago

Explain what kind of heat transfer occurs when you burn yourself on a hot car seat in the summer.

liubo4ka [24]

Conduction is a mode of transfer of heat there

6 0

3 years ago

While water skiing behind her father’s boat, Letty is pulled at constant speed by a force of 164 N from the tow rope that makes

kap26 [50]

Answer:

0.265

Explanation:

Draw a free body diagram. There are four forces:

Normal force Fn pushing up.

Weight force mg pulling down.

Tension force T at an angle θ.

Friction force Fn μ pushing left.

Sum the forces in the y direction:

∑F = ma

Fn + T sin θ − mg = 0

Fn = mg − T sin θ

Sum the forces in the x direction:

∑F = ma

T cos θ − Fn μ = 0

Fn μ = T cos θ

μ = T cos θ / Fn

μ = T cos θ / (mg − T sin θ)

Given T = 164 N, θ = 10.0°, m = 65.0 kg, and g = 9.8 m/s²:

μ = (164 N cos 10.0°) / (65.0 kg × 9.8 m/s² − 164 N sin 10.0°)

μ = 0.265

7 0

2 years ago

A flywheel in a motor is spinning at 510 rpm when a power failure suddenly occurs. The flywheel has mass 40.0 kg and diameter 75

8_murik_8 [283]

Complete Question

A flywheel in a motor is spinning at 510 rpm when a power failure suddenly occurs. The flywheel has mass 40.0 kg and diameter 75.0 cm . The power is off for 40.0 s , and during this time the flywheel slows down uniformly due to friction in its axle bearings. During the time the power is off, the flywheel makes 210 complete revolutions. At what rate is the flywheel spinning when the power comes back on(in rpm)? How long after the beginning of the power failure would it have taken the flywheel to stop if the power had not come back on, and how many revolutions would the wheel have made during this time?

Answer:

$\theta=274rev$

Explanation:

From the question we are told that:

Angular velocity $\omega=510rpm$

Mass $m=40.kg$

Diameter d $75=>0.75m$

Off Time $t=40.0s$

Oscillation at Power off $N=210$

Generally the equation for Angular displacement is mathematically given by

$\theta_{\infty}=\frac{w+w_0}{t}t$

$w=\frac{2*\theta_{\infty}}{t}-w_0$

$w=\frac{28210}{40*(\frac{1}{60})}-510$

$w=120rpm$

Generally the equation for Time to come to rest is mathematically given by

$t=(\frac{\omega_0}{\omega_0-\omega})t$

$t=(\frac{510}{510-120rpm})(40.0)(\frac{1}{60})$

$t=0.87min$

Therefore Angular displacement is

$\theta =(\frac{120+510}{2})0.87$

$\theta=274rev$

6 0

2 years ago

What does Kepler's first law of planetary motion imply?

BlackZzzverrR [31]

Answer:

The correct answer option is D. The distance between the planet and the Sun changes as the planet orbits the sun.

Explanation:

Kepler’s laws of planetary motion, derived by the German astronomer Johannes Kepler, are the laws of physics that describe the motions of the planets in the solar system.

According to the Kepler's first law of planetary motion: the path on which the planets orbit around the sun is elliptical in shape, with the center of the sun at one focus.

Therefore, the distance between the Sun and the planets vary as the planet orbit around the sun.

6 0

3 years ago