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Physics

Jaliyah

Which of Newton's laws, when combined algebraically with his law of universal gravitation, can be used to calculate Earth's mass?

A) first

B) second

C) third

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Physics

Roscoe

Why does a balloon filled with helium rise while a balloon filled with an equal volume of average atmospheric air does not?

A. Helium has no mass, but air does.

B. Helium increases the balloon's mass more than air.

C. Helium has a higher density than air.

D. Helium has a lower density than air.

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Physics

Guest

Consider the following controls in an automobile in motion : gas pedal, brake, steering wheel. what are the controls in this list that cause an acceleration of the car?

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Physics

Hunter Shelton

What material are oil pipelines made from?

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Physics

Elliana Sloan

3/129 A 175-lb pole vaulter carrying a uniform 16-ft, 10-lb pole approaches the jump with a velocity v and manages to barely clear the bar set at a height of 18 ft. As he clears the bar, his velocity and that of the pole are essentially zero. Calculate the minimum possible value of v required for him to make the jump. Both the horizontal pole and the center of gravity of the vaulter are 42 in. above the ground during the approach.

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Physics

Brianna Chambers

A few years ago, Serena Williams dived to hit a tennis ball right after it bounced off the ground. The ball bounced on the ground 10.3 m from the net, and after Serena hit the ball it flew over the 0.950 m high net and bounced in her opponent's court about 0.970 s after she hit it. If there had been no gravity, the ball would have been 1.36 m higher than the net when it crossed over. How fast was the ball moving when it left Serena/'s racket? Ignore any effects from ball spin and air resistance.

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Physics

Juan Waller

A force of 1.25x103N is required to lift an object that is under the influence of an acceleration due to gravity of 7.86ft/sec2. What is the object's mass in kilograms?

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Physics

Mohammad Glenn

Which of these events is an example of the Doppler shift?

The amplitude of a wave on a string increases as the frequency decreases.

The amplitude of sound from a tuning fork decreases due to damping.

The frequency of light from a star increases as it moves toward us.

The intensity of an electromagnetic wave increases with the field strength.

The velocity of an electromagnetic wave changes as its medium changes.

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Physics

Figaro

One disadvantage of this type of power is that it still pollutes the air.

biomass

geothermal power

hydropower

solar power

You want to create a new warming appliance that is safe. Which type of electromagnetic wave would be most useful to investigate?

X-rays

infrared waves

gamma rays

ultraviolet waves

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Physics

Noel Browning

A small rock remains at rest in outer space while an astronaut pushes horizontally on it with a force of 20 N. Which of the following must be true? A. There is another horizontal force acting on the rock. B. There are vertical forces acting on the rock. C. The rock is extremely massive. D. The rock does not feel the gravitational pull of Earth.

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Physics

Louis Mann

If an igneous rock has very large crystals of minerals that you can see when looking at it, which type of igneous rock is it

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Physics

Nibbles

You have a 60-foot roll of fencing and a large field. You want to make two paddocks by continuing the fencing down the middle of a rectangular enclosure. What are the dimensions of the largest such enclosure you can make?

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Physics

Marcel Fisher

Crystallization is a separation technique used to produce rock candy from a sugar solution. true or false

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Physics

Felicity Fritz

A car traveling in a straight line has a velocity of 3.79 m/s at some instant. After 5.4 s, its velocity is 11.9 m/s. What is its average acceleration in this time interval? Answer in units of m/s 2

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Physics

Charlize Lloyd

The periodic law states that elements that have similar properties appear ...

a. to the left of each other

b. to the right of each other

c. at every 10th element

d. at regular intervals

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