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2 years ago

Helpppppp meeeee plzzzz

Physics

2 answers:

Elza [17]2 years ago

7 0

(19 is 4) and (20 is 3).hope this works.

pychu [463]2 years ago

3 0

19) 4. Gas prices are increasing, but ethanol is made from corn, something fairly cheap.

20) 3. It also releases CO2 (carbon dioxide) like gasoline.

Hope this helped!

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A tow truck exerts a force of 3000 n on a car, accelerating it at 2 meters per second per second. what is the mass of the car?

Artemon [7]

If the force is 3,000 N and the acceleration is 2 m/s/s. The mass of the car is 1,500 grams (or whatever unit of mass or weight is used in the answer- pounds, kilograms e.t.c.).

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2 years ago

A 7.5 kg block is placed on a table. if it's bottom surface area is 0.6m2, how much pressure does the block exert on the tableto

xeze [42]

The answer to this is B.

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2 years ago

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2 years ago

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The river narrows at a rapids from a width of 12 m to a width of only 5.8 m. The depth of the river before the rapids is 2.7 m;

Alisiya [41]

Answer:

7.89 m/s

Explanation:

Given that

Width of the river, b1 = 12 m

Width of the river, b2 = 5.8 m

Depth of the river, d1 = 2.7 m

Depth of the river, d2 = 0.85 m

Speed of the river, v1 = 1.2 m/s

Speed of the river, v2 = ?

Area of the river before the rapid, a1 = 12 * 2.7 = 32.4 m²

Area of the river after the rapid, a2 = 5.8 * 0.85 = 4.93 m²

To solve this question, we use a relation between the speed of the river and the volume of the river. We say,

Area1 * velocity1 = Area2 * velocity2, and when we substitute the values for each other we have

32.4 * 1.2 = 4.93 * v2

38.88 = 4.93v2

v2 = 38.88 / 4.93

v2 = 7.89 m/s

Therefore, the speed of the river after the rapid is 7.89 m/s

6 0

1 year ago

Change in Energy Quick Check

nika2105 [10]

Answer:

The force of gravity on the object decreases. (FALSE)

The potential energy of the object decreases. (TRUE)

The acceleration due to gravity decreases. (FALSE)

The kinetic energy of the object decrease (FALSE)

Explanation:

FORCE OF GRAVITY:

Force of gravity on the object is the weight of object, which depends upon the mass and value of acceleration due to gravity (W = mg). Since, the value mass is constant on Earth and acceleration due to gravity is also constant on earth.

Therefore, force of gravity remains same on the object. The statement is false.

POTENTIAL ENERGY:

Potential energy of object depends upon the mass, value of acceleration due to gravity, and change in height of object (P.E = mgΔh). Since, the value mass is constant on Earth and acceleration due to gravity increases as the object moves towards the surface of earth. But, the height of object is decreasing.

Therefore, potential energy of object decreases. The statement is true.

ACCELERATION DUE TO GRAVITY:

Acceleration due to gravity depends upon the altitude (gh = g[1 - 2h/Re]). Since, the height of object is decreasing.

Therefore, acceleration due to gravity increases. The statement is false.

But, this change is not significant.

KINETIC ENERGY:

Kinetic Energy of object, which depends upon the mass and velocity of the object (K.E = mv²/2). Since, the value mass is constant on Earth and velocity increases as the object moves towards the surface of earth.

Therefore, kinetic energy of the object also increases. The statement is false.

4 0

2 years ago