25 pt. 5 pt. 10 pt. 15 pt. 20 pt. 25 pt. 5 pt. 10 pt. 15 pt. 20 pt. 25 pt. 5 pt. 10 pt. 15 pt. 20 pt. 25 pt. 5 pt. 10 pt. 15 pt. 20 pt. 25 pt. 5 pt. 10 pt. 15 pt. 20 pt.

1-5 When energy is added to an object, what kind of work is done? A) positive B) negative C) zero D) not enough info

1-5A When energy is added to an object, what kind of work is done? A) positive

1-10 Is the work done on the object pictured below positive or negative? distance Force

1-10A 0 N, since the force and distance are at right angles. Is the work done on the object pictured below positive or negative? distance Force

1-15 How much work is done by a car’s engine when it pushes the 2000 kg car with a force of 1450 N through a distance of 200 meters?

1-15A How much work is done by a car’s engine when it pushes the 2000 kg car with a force of 1450 N through a distance of 200 meters? Work = Force x distance Work = (1450 N)(200 m) = 290,000 J

1-20 How many watts are expended when a 100-N person walks 3.5 meters up a flight of stairs in 14 seconds?

1-20A How many watts are expended when a 100-N person walks 3.5 meters up a flight of stairs in 14 seconds? Work = Force x distance Work = (100 N)(3.5 m) = 350 J Power = Work / Time Power = (350 J)/(14 sec) = 25 Watts

4-20A When jumping off of a 3m tall garage, the 90 kg jumper lands on a pile of leaves. How much work does the pile of leaves do on the jumper?

4-20A W = ∆KE = -∆PE g = -mgh W = - 90kg * 10m/s 2 * 3m W = J When jumping off of a 3m tall garage, the 90 kg jumper lands on a pile of leaves. How much work does the pile of leaves do on the jumper?

2-5 Negative work is done on a rolling bowling ball. What happens to the kinetic energy of the ball? A) KE increases B) KE does not change C) KE decreases D) not enough info

2-5A Negative work is done on a rolling bowling ball. What happens to the kinetic energy of the ball? C) KE decreases

2-10 True or False: It is possible for an object to have a negative kinetic energy.

2-10A False True or False: It is possible for an object to have a negative kinetic energy.

2-15 What is the KE of a car with a mass of 1200-kg that is moving at 180 km/hr?

2-15A KE = 1 / 2 mv km/hr = 50 m/s KE = 1 / 2 (1200 kg)(50 m/s) 2 KE = 1,500,000 Joules What is the KE of a car with a mass of 1200-kg that is moving at 180 km/hr?

2-20 Two identical cars are traveling down the road -- one moving at twice the speed of the other. If both apply the brakes, what will happen? A) they both travel the same distance B) the faster car will move twice as far C) the faster car will move four times as far D) not enough info

2-20A Two identical cars are traveling down the road -- one moving at twice the speed of the other. If both apply the brakes, what will happen? C) the faster car will move four times as far

2-25 A rocket of mass 250-kg is launched upward by a thrust force of 10,000-N through 12 kilometers. How fast is it moving when the engine shuts off?

2-25A Work = Change in Energy Fd = mgh + 1 / 2 mv 2 (10,000N)(12,000m) = (250kg)(10)(12,000m)+ 1 / 2 (250 kg)v 2 v = √[720,000] v = 849 m/sec A rocket of mass 250-kg is launched upward by a thrust force of 10,000-N through 12 kilometers. How fast is it moving when the engine shuts off?

3-5 How do you calculate gravitational potential energy (GPE)?

3-5A GPE = weight x height = mgh How do you calculate gravitational potential energy (GPE)?

3-10 What is the PE g of a 50-kg object placed at a height of 10 m?

3-10A PE g = mgh = (50 kg)(10 m/s 2 )(10 m) PE g = 5,000 Joules What is the PE g of a 50-kg object placed at a height of 10 m?

3-15 If 72J of work is done on a spring with a spring constant of 16, how far is the spring stretched?

3-15A If 72J of work is done on a spring with a spring constant of 16, how far is the spring stretched? W =  PE S = 72J PE S = ½ kx 2 72J = ½ kx 2 9 = x 2 x = 3m

3-20 A vertical spring is compressed 0.4m by a 24kg mass. The mass is removed, allowing the spring to return to normal. The spring is then stretched 0.8m. How much energy is in the spring?

3-20A F = kx 24kg * 10m/s 2 = k * 0.4m k = 600 N/m PE S = ½ kx 2 PE S = 192 J A vertical spring is compressed 0.4m by a 24kg mass. The mass is removed, allowing the spring to return to normal. The spring is then stretched 0.8m. How much energy is in the spring?

3-25

3-25A GPE = (2300 kg)(10 m/s 2 )(38 m) = 874,000 J Power = GPE / Time = (874,000 J)/(60 sec) Power = 14,567 Watts How much power does the engine of a 2300-kg elevator put out if it climbs through 38-m in one minute?

4-5 If the universe began during the Big Bang 15 billion years ago with an energy of 516 gadzillion Joules, how much energy is there in the universe right now?

4-5A If the universe began during the Big Bang 15 billion years ago with an energy of 516 gadzillion Joules, how much energy is there in the universe right now? 516 gadzillion Joules

4-10 When a car slows down to a stop where does all of its previous KE go? A) it turns into heat B) braking energy C) into total mechanical energy D) not enough info

4-10A When a car slows down to a stop where does all of its previous KE go? A)it turns into heat

4-15 When a diver who weighs 650-N jumps from a 10-m high diving platform, how much KE do they hit the water with?

4-15A GPE initial = KE final KE final = (650 N)(10 m) = 6500 J When a diver who weighs 650-N jumps from a 10-m high diving platform, how much KE do they hit the water with?

4-20 When jumping up and down on a trampoline, the 45-kg jumper leaves the trampoline with a KE of 3800 J. How high do they travel?

4-20A KE initial = GPE final = mgh 3800 J = (450 N) h h = (3800 J)/(450 N) = 8.44 m When jumping up and down on a trampoline, the 45-kg jumper leaves the trampoline with a KE of 3800 J. How high do they travel?

4-25 A 2-kg ball slides from rest down a 5-m tall incline as shown. When it is halfway down, how fast is it going?

4-25A GPE initial = KE + GPE (2kg)(10m/s 2 )(5m) = 1 / 2 (2kg)v 2 + (2kg)(10m/s 2 )(2.5m) 100 J = 1 / 2 (2kg)v J 50 J = v 2 v = √(50) = 7.1 m/sec A 2-kg ball slides from rest down a 5-m tall incline as shown. When it is halfway down, how fast is it going?

5-5 What’s the anagram of the following phrase which is also the name of a famous actor of that movie genre? Old West Action

5-5A Clint Eastwood Old West Action

5-10 Name the character and movie that produced this famous quote: “A wizard is never late… he arrives precisely when he means to.”

5-10A Gandalf the Grey, in LOTR: Fellowship of the Ring

5-15 Launched in 1977, what spacecraft is now the farthest from Earth?

5-15A Voyager I

5-20 In what year was the Great Pyramid of Giza constructed? (±300 years)

5-20A Roughly 2600 B.C.E.

5-25 Who is the vicious ruler of the planet Mongo, and the enemy of Flash Gordon?

5-25A Ming the Merciless

Daily Double How much power does the engine of a 2300-kg elevator put out if it climbs through 38-m in one minute?