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Anit [1.1K]
3 years ago
10

How many foot-pounds of work does it take to throw a baseball 90 mph? a baseball weighs 5 oz, or 0.3125 lb?

Physics
1 answer:
NARA [144]3 years ago
5 0

Kinetic energy of the ball is (mv²) / 2, where m is the mass and v is the velocity

So plugging in the mass and the velocity into the kinetic energy expression, you get:

Kinetic energy of the ball = (mv²) / 2

(0.3125/32) times (132)² divided by 2 = 85 ft-lbs


Kinetic energy of the ball = 85 ft-lbs


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Answer:

U = 80.91 J

Explanation:

In order to calculate the electric potential energy between the three charges you use the following formula:

U=k\frac{q_1q_2}{r_{1,2}}                  (1)

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q1: q2 charge

r1,2: distance between charges 1 and 2.

For the three charges you have:

U_T=k\frac{q_1q_2}{r_{1,2}}+k\frac{q_1q_3}{r_{1,3}}+k\frac{q_2q_3}{r_{2,3}}           (2)

You use the fact that q1=q2=q3=q and that the distance between charges are equal. Then, in the equation (2) you have:

q = 1.45μC = 1.45*10^-6C

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3 years ago
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Answer:

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Explanation:

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E. Kepler's second law says the planet must move fastest when it is closest, not  when it is farthest away.

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