inch. If the handle travels 3 feet per revolution, what is the mechanical advantage of the jack?
Answers
- c. The 20-pound block is located closer to scale 1 than scale 2. Scale 1 will support more than half the weight of the block.
- c. w1 × d1 = w2 × d2.Todd is 6 feet away from the pivot point, and the block is 18 feet away. 50 × 18 feet = 6 feet × w2. Solving for w2 gives 150 pounds.
- b. When air is heated it expands and becomes less dense than cold air, making the entire balloon buoyant and allowing it to float.
- d. Mechanical advantage describes the factor that force is multiplied by a simple machine. Here, by moving the screw handle 3 feet , the jack is raised
inch. Thus the mechanical advantage of the jack is 36 ÷ = 144. - d. A pulley system of this type has a mechanical advantage of 4. So, if Bryan can pull a rope with 150 pounds of force, he will be able to lift a weight of 150 pounds × 4 = 600 pounds.
- d. Mechanical advantage = output force ÷ input force. Here, 20 pounds of force is input to lift 80 pounds of dirt. The mechanical advantage is 80 ÷ 20 = 4.
- a. Mechanical advantage (MA) is the factor by which a simple machine multiplies for the force put into it. In this case, 120 pounds of force is used to move a 360-pound block, so MA = 360 ÷ 120 = 3. The MA of a ramp is determined by the length of the ramp, l, divided by the height gained, h. In this case,
. Solving for l tells us the ramp is 30 feet long. - d. The force required to stretch a spring is equal to its force constant multiplied by the distance stretch (F = kx). The force required to move a spring with a force constant of 3 pounds per inch a distance of 12 inches is 3 × 12 = 36 pounds.
- d. Since pulley A is three times greater in diameter than pulley A, each revolution of A will lead to 3 revolutions of B. If A rotates at 45 rpm, then B will rotate at 45 rpm × 3 = 135 rpm.
- d. Friction is the force that must be overcome in order to slide on object across another.
- b. There are 6 threads per inch. To move the nut 2 inches will require 6 × 2 = 12 turns.
- c. Water pressure at the bottom of a tank increases as the weight of water above it increases, but pressure at the top remains the same, since it has a finite amount of water above it.
- a. The entire weight is supported by a single cable and no mechanical advantage is achieved using this pulley system. So the mechanical advantage is 1.
- c. All other materials are denser than water and will sink. Styrofoam is not very dense and will float on water.
- c. Gear 1 turning clockwise will cause gear 2 to turn counterclockwise. In turn, this counterclockwise movement will cause gears 3 and 4 to turn clockwise.
- d. The 200-pound weight will stretch the first spring 200 pounds ÷ 400 pounds per inch = 0.5 inches. The second spring stretches 200 pounds ÷ 200 pounds per inch = 1 inch. The third spring stretches 200 pounds ÷ 100 pounds per inch = 2 inches. The total amount the platform compresses is therefore 0.5 + 1 + 2 = 3.5 inches.
- d. Since the two are traveling in opposite directions, the rate at which they move farther apart is equal to the sum of their two speeds (35 mph + 45 mph = 80 mph). After 2 hours, the two will be 80 mph × 2 hours = 160 miles.
- b. The first bike has 12 teeth on its rear cog and 52 teeth on front chain ring. At 60 rpm, the bike will travel 60 rpm × 52 front teeth ÷ 12 rear teeth = 260 revolutions. For the bicycle with 14 teeth on its rear cog to travel 260 revolutions, it must be pedaled at 260 revolutions × 14 teeth ÷ 52 front teeth = 70 rpm.
- b. If the container is being filled at 18 gallons per minute (gpm) and evacuated at 14 gpm, then it is filling at an overall rate of (18 – 14 = 4 gpm). Since the tank can hold 20 gallons, it will fill in 20 gallons ÷ 4 gallons per minute = 5 minutes.
- a. w1 × d1 = w2 × d2. 96 pounds × 5 feet =w2 × 12 feet. Solving for w2 gives 40 pounds.
- b. The mechanical advantage (MA) of a ramp is determined by the length of the ramp, l, divided by the height gained, h. In this case,
. The force required to pull a 800-pound block up a ramp is 800 pounds ÷ 5 = 160 pounds. - d. Every full turn of the larger gear will result in 18 teeth ÷ 12 teeth = 1.5 rotations. In two turns of the larger gear, the smaller will complete 3 rotations.
- a. The lip of the paint can acts as a fulcrum of a lever when trying to pry off a lid. The long arm of a screwdriver provides a sizeable mechanical advantage.
- a. w1 × d1 = w2 × d2. Stevi is 14 feet away from the pivot point. 70 pounds × 9 feet = 14 feet × w2. Solving for w2 gives 45 pounds.
- c. A pulley system of this type has a mechanical advantage of 2. So, to lift a 150-pound weight will require 150 pounds ÷ 2 = 75 pounds.
- 1
-
2
View Full Article
Excerpted From:
From ASVAB: Power Practice. Copyright © 2010 by LearningExpress, LLC. All Rights Reserved.
Add your own comment
Ask a Question
Have questions about this article or topic? Ask150 Characters allowed
Related Questions
See More QuestionsToday on Education.com
5 Outdoor Games to Play in Under 5 Minutes 
Spring Fever! 6 Ways to Settle Kids Down 
6 Teacher Tips You Can Use at Home Popular Articles
Wondering what others found interesting? Check out our most popular articles.
- Kindergarten Sight Words List
- The Five Warning Signs of Asperger's Syndrome
- What Makes a School Effective?
- Child Development Theories
- Why is Play Important? Social and Emotional Development, Physical Development, Creative Development
- 10 Fun Activities for Children with Autism
- Test Problems: Seven Reasons Why Standardized Tests Are Not Working
- Bullying in Schools
- A Teacher's Guide to Differentiating Instruction
- Steps in the IEP Process
