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Day 7 Item Analysis

Day 7 Item Analysis. The weight lifter used a force of 980 N to raise the barbell over her head in 5.21 seconds. Approximately how much work did she do in raising the barbell? A 380 J B 982 J C 2,000 J D 10,000 J. The correct answer is C.

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Day 7 Item Analysis

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  1. Day 7 Item Analysis

  2. The weight lifter used a force of 980 N to raise the barbell over her head in 5.21 seconds. Approximately how much work did she do in raising the barbell? A 380 J B 982 J C 2,000 J D 10,000 J

  3. The correct answer is C. The weight lifter used a force of 980 N to raise the barbell over her head in 5.21seconds. Approximately how much work did she do in raising the barbell? Given: Force = 980 N Time = 5.21 seconds Height = 2.04 m • From formula chart: Work = force x distance • Work = 980 N x 2.04 m = 1999.2 or 2000 Nm= 2000J

  4. How many newtons of force does a 50.0 kg deer exert on the ground because of gravity?

  5. How many newtons of force does a 50.0 kgdeer exert on the ground because of gravity? Given: 50.0 kg deer (mass) Gravity (from formula chart acceleration due to gravity = 9.8 m/s2 Unknown: Newtons (unit of force) From formula chart Then: Force + 50.0 kg x 9.8 m/s2 = 490 N The correct answer is C

  6. Observing an approaching thunderstorm and using a stopwatch, a student finds that it takes 8.40 seconds for thunder to be heard after a lightning bolt strikes. The student has learned that it takes 3.0 seconds for sound to travel 1000 m. How far away is the storm? A 119 m B 185 m C 2800 m D 8400 m

  7. Observing an approaching thunderstorm and using a stopwatch, a student finds that it takes 8.40 seconds for thunder to be heard after a lightning bolt strikes. The student has learned that it takes 3.0 seconds for sound to travel 1000 m. How far away is the storm? The correct answer is C. From the information sound travel 1000m 3 sec and Then: speed of sound = 333m = _m___ sec 8.40 sec = 2800 m

  8. Which bike rider has the greatest momentum? A A 40 kg person riding at 45 km/h B A 50 kg person riding at 35 km/h C A 60 kg person riding at 25 km/h D A 70 kg person riding at 15 km/h

  9. The correct answer is A. • From the formula chart A Momentum = 40 kg x 45 km/h= 1800 kgxkm/h B Momentum = 50 kg x 35 km/h= 1750 kgxkm/h C Momentum = 60 kg x 25 km/h= 1500 kgxkm/h D Momentum = 70 kg x 15 km/h= 1050 kgxkm/h The correct answer is A

  10. How much force is needed to accelerate a 1,300 kg car at a rate of 1.5 m/s2? A 867 N B 1,950 N C 8,493 N D 16,562 N

  11. How much force is needed to accelerate a 1,300 kg car at a rate of 1.5 m/s2? From the formula chart Therefore: Force = 1300 kg x 1.5 m/s2 = 1950 N The correct answer is B

  12. What is the current in a copper wire that has a resistance of 2 ohms and is connected to a 9-volt electrical source? A0.22 amps B 4.5 amps C11.0 amps D18.0 amps

  13. The correct answer is B What is the current in a copper wire that has a resistance of 2 ohms and is connected to a 9-volt electrical source? • From the formula chart • Current = 9 V___ = 4.5 amps 2 ohms

  14. How much work is performed when a 50 kg crate is pushed 15 m with a force of 20 N? A 300 J B750 J C 1,000 J D15,000 J

  15. The correct answer is A. How much work is performed when a 50 kg crate is pushed 15 m with a force of 20 N? According to the formula chart Therefore: Work = 20 N x 15m = 300 J

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