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Debora [2.8K]
3 years ago
11

1. An 80-kg quarterback jumps straight up in the air right before throwing a 0.43-kg football horizontally at 15 m/s. How fast w

ill he be moving backward just after releasing the ball?2. Which of the following best describes why you can analyze this event using conservation of momentum?A. The throwing action is quick enough that external forces may be ignored.B. External forces don't act on the system during the jump.C. Conservation of momentum is always the best way to analyze motion.
Physics
1 answer:
algol133 years ago
4 0

Answer:

1) 0.0806 m/s

2) External forces don't act on the system during the jump

Explanation:

velocity of ball ( Vbf )= 15 m/s

mass of quarter back ( Mq )= 80 kg

mass of football ( Mb ) = 0.43 kg

A) How fast will be be moving backward just after releasing the ball

we can determine this speed with the use of conservation of momentum equation

= Mb ( Vbf - Vbi ) = Mq ( Vq )

where Vq = Mb ( Vbf - Vbi ) / Mq

                 = 0.43 ( 15 m/s - 0 ) / 80 kg

                 = 0.0806 m/s

B) External forces don't act on the system during the jump

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g Two radiation modes (one at the center frequency lIo and the other at lIO+?lI) are excited with 1000 photons each. Determine t
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Explanation:

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the stimulated emission rate is equal to:

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where

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b) the rate of decay is equal to:

R=B*N2*E, where B is the Einstein´s coefficient and E is the energy system

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7 0
3 years ago
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Answer:

T = 8.55 N

Explanation:

When string makes an angle 40 degree with the vertical then it will have two forces on it

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T - mg cos40 = F_c

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T = 3 + \frac{0.40\times 5^2}{1.8}

T = 3 + 5.55

T = 8.55 N

6 0
3 years ago
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