Algebra Word Problems Lesson 9 Worksheet 9 Algebra Word Problems Involving Levers 1 © MathTutorDVD.com Algebra Word Problems – Lesson 9, Worksheet 9, Algebra Word Problems Involving Levers Problem 1) Jacob weighs 90 pounds and sits 6 feet from the fulcrum of a seesaw. If Sally weighs 120 pounds and sits on the other side, how many feet from the fulcrum must she sit to have the seesaw balance? Problem 2) At one end of a lever is a 14 kg weight which is 9 meters from the fulcrum. How much weight, in kg, should be placed on the other end 18 meters from the fulcrum to balance? Problem 3) A person places a lever under a 240 pound weight that is 6 feet from the fulcrum. In order to lift the rock, how much force must the person on the other end of the lever, if he is 9 feet from the fulcrum? 2 © MathTutorDVD.com Problem 4) Where should the fulcrum, in feet, be placed under a 12 meter lever if there is a 24 kg weight on one end and a 36 kg weight on the other end in order to balance? Problem 5) Brian weighs 56 kg and sits 1.8 meters from the fulcrum of a seesaw. If Lisa weighs 48 kg and sits on the other side, how far, in meters, from the fulcrum must she sit to have the seesaw balance? Problem 6) At one end of a lever is a 150 kg engine which is 2 meters from the fulcrum. How much weight, in kg, should be placed on the other end 3 meters from the fulcrum to balance? 3 © MathTutorDVD.com Problem 7) A forklift places a lever under a 250 pound tank that is 8 feet from the fulcrum. In order to lift the rock, how much force, in pounds, must the forklift on the other end of the lever, if it is 10 feet from the fulcrum? Problem 8) Approximately where, in meters, should the fulcrum be placed under a 15 meter lever if there is a 24 kg weight on one end and a 20 kg weight on the other end in order to balance? Problem 9) Randy weighs 217 pounds and sits 6 feet from the fulcrum of a seesaw. If Joe weighs 186 pounds and sits on the other side, how far from the fulcrum must he sit to have the seesaw balance? 4 © MathTutorDVD.com Problem 10) At one end of a lever is a 40 kg weight which is 6 meters from the fulcrum. How much weight should be placed on the other end 1.5 meters from the fulcrum to balance? Problem 11) A person places a lever under a 18 pound cement block that is 3 feet from the fulcrum. In order to lift the rock, how much force, in pounds, must the person on the other end of the lever, if he is 6 feet from the fulcrum? Problem 12) Approximately where, in meters, should the fulcrum be placed under a 8 meter lever if there is a 48 kg weight on one end and a 64 kg weight on the other end in order to balance? 5 © MathTutorDVD.com Problem 13) Leonard weighs 208 pounds and sits 7 feet from the fulcrum of a seesaw. If Mark weighs 182 pounds and sits on the other side, how far, in feet, from the fulcrum must he sit to have the seesaw balance? Problem 14) At one end of a lever is a 5.8 kg weight which is 2.4 meters from the fulcrum. How much weight, in kg, should be placed on the other end 1.6 meters from the fulcrum to balance? Problem 15) A person places a lever under a 16.1 pound rock that is 4.8 feet from the fulcrum. In order to lift the rock, how much force, in pounds, must the person on the other end of the lever, if he is 5.6 feet from the fulcrum? 6 © MathTutorDVD.com Problem 16) Approximately where, in meters, should the fulcrum be placed under a 14 meter lever if there is a 9 kg weight on one end and a 6 kg weight on the other end in order to balance? Problem 17) Clarence weighs 154 pounds and sits 6 feet from the fulcrum of a seesaw. If Kathy weighs 132 pounds and sits on the other side, how far, in feet, from the fulcrum must she sit to have the seesaw balance? Problem 18) At one end of a lever is a 320 kg weight which is 5 meters from the fulcrum. How much weight, in kg, should be placed on the other end 8 meters from the fulcrum to balance? 7 © MathTutorDVD.com Problem 19) A person places a lever under a 180 pound rock that is 12 feet from the fulcrum. In order to lift the rock, how much force, in pounds must the person on the other end of the lever, if he is 24 feet from the fulcrum? Problem 20) Where should, in meters, the fulcrum be placed under a 12 meter lever if there is a 10 kg weight on one end and a 8 kg weight on the other end in order to balance? 8 © MathTutorDVD.com Answers - Algebra Word Problems – Lesson 9, Worksheet 9, Algebra Word Problems Involving Levers Problem 1) Jacob weighs 90 pounds and sits 6 feet from the fulcrum of a seesaw. If Sally weighs 120 pounds and sits on the other side, how many feet from the fulcrum must she sit to have the seesaw balance? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 90 ∙ 6 = 120 ∙ 𝑙 540 = 120 ∙ 𝑙 𝑙= 540 = 4.5 120 Answer: 4.5 Problem 2) At one end of a lever is a 14 kg weight which is 9 meters from the fulcrum. How much weight, in kg, should be placed on the other end 18 meters from the fulcrum to balance? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 14 ∙ 9 = 𝑤 ∙ 18 126 = 18𝑤 𝑤= 126 =7 18 Answer: 7 9 © MathTutorDVD.com Problem 3) A person places a lever under a 240 pound weight that is 6 feet from the fulcrum. In order to lift the rock, how much force must the person on the other end of the lever, if he is 9 feet from the fulcrum? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 240 ∙ 6 = 𝑤 ∙ 9 1440 = 9𝑤 𝑤= 1440 = 160 9 Answer: 160 Problem 4) Where should the fulcrum, in feet, be placed under a 12 meter lever if there is a 24 kg weight on one end and a 36 kg weight on the other end in order to balance? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 𝑙 ∙ 24 = (12 − 𝑙) ∙ 36 24𝑙 = 432 − 36𝑙 48𝑙 = 432 𝑙= 432 =9 48 Answer: 9 10 © MathTutorDVD.com Problem 5) Brian weighs 56 kg and sits 1.8 meters from the fulcrum of a seesaw. If Lisa weighs 48 kg and sits on the other side, how far, in meters, from the fulcrum must she sit to have the seesaw balance? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 1.8 ∙ 56 = 48 ∙ 𝑙 100.8 = 48𝑙 𝑙= 100.8 = 2.1 48 Answer: 2.1 Problem 6) At one end of a lever is a 150 kg engine which is 2 meters from the fulcrum. How much weight, in kg, should be placed on the other end 3 meters from the fulcrum to balance? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 150 ∙ 2 = 𝑤 ∙ 3 300 = 3𝑤 𝑤= 300 = 100 3 Answer: 100 11 © MathTutorDVD.com Problem 7) A forklift places a lever under a 250 pound tank that is 8 feet from the fulcrum. In order to lift the rock, how much force, in pounds, must the forklift on the other end of the lever, if it is 10 feet from the fulcrum? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 250 ∙ 8 = 𝑤 ∙ 10 2000 = 10𝑤 𝑤= 2000 = 200 10 Answer: 200 Problem 8) Approximately where, in meters to the nearest tenth, should the fulcrum be placed under a 15 meter lever if there is a 24 kg weight on one end and a 20 kg weight on the other end in order to balance? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 𝑙 ∙ 24 = (15 − 𝑙) ∙ 20 24𝑙 = 300 − 20𝑙 44𝑙 = 300 𝑙= 300 = 6.8 44 Answer: 6.8 12 © MathTutorDVD.com Problem 9) Randy weighs 217 pounds and sits 6 feet from the fulcrum of a seesaw. If Joe weighs 186 pounds and sits on the other side, how far from the fulcrum must he sit to have the seesaw balance? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 217 ∙ 6 = 𝑙 ∙ 186 1302 = 186𝑙 𝑙= 1302 =7 186 Answer: 7 Problem 10) At one end of a lever is a 40 kg weight which is 6 meters from the fulcrum. How much weight should be placed on the other end 1.5 meters from the fulcrum to balance? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 40 ∙ 6 = 1.5 ∙ 𝑤 240 = 1.5𝑤 𝑤= 240 = 160 1.5 Answer: 160 13 © MathTutorDVD.com Problem 11) A person places a lever under a 18 pound cement block that is 3 feet from the fulcrum. In order to lift the rock, how much force, in pounds, must the person on the other end of the lever, if he is 6 feet from the fulcrum? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 18 ∙ 3 = 6 ∙ 𝑤 54 = 6𝑤 𝑤= 54 =9 6 Answer: 9 Problem 12) Approximately where, in meters to the nearest tenth, should the fulcrum be placed under a 8 meter lever if there is a 48 kg weight on one end and a 64 kg weight on the other end in order to balance? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 𝑙 ∙ 48 = (8 − 𝑙)64 48𝑙 = 512 − 64𝑙 112𝑙 = 512 𝑙= 512 = 4.571428~4.6 112 Answer: 4.6 14 © MathTutorDVD.com Problem 13) Leonard weighs 208 pounds and sits 7 feet from the fulcrum of a seesaw. If Mark weighs 182 pounds and sits on the other side, how far, in feet, from the fulcrum must he sit to have the seesaw balance? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 208 ∙ 7 = 𝑙 ∙ 182 1456 = 182𝑙 𝑙= 1456 =8 182 Answer: 8 Problem 14) At one end of a lever is a 5.8 kg weight which is 2.4 meters from the fulcrum. How much weight, in kg, should be placed on the other end 1.6 meters from the fulcrum to balance? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 2.4 ∙ 5.8 = 𝑙 ∙ 1.6 13.92 = 1.6𝑙 𝑙= 13.92 = 8.7 1.6 Answer: 8.7 15 © MathTutorDVD.com Problem 15) A person places a lever under a 16.1 pound rock that is 4.8 feet from the fulcrum. In order to lift the rock, how much force, in pounds to the nearest tenth, must the person on the other end of the lever, if he is 5.6 feet from the fulcrum? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 16.1 ∙ 4.8 = 5.6 ∙ 𝑤 77.28 = 5.6𝑤 𝑤= 77.28 = 13.8 5.6 Answer: 13.8 Problem 16) Approximately where, in meters to the nearest tenth, should the fulcrum be placed under a 14 meter lever if there is a 9 kg weight on one end and a 6 kg weight on the other end in order to balance? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 𝑙 ∙ 9 = (14 − 𝑙) ∙ 6 9𝑙 = 84 − 6𝑙 15𝑙 = 84 𝑙= 84 = 5.6 15 Answer: 5.6 16 © MathTutorDVD.com Problem 17) Clarence weighs 154 pounds and sits 6 feet from the fulcrum of a seesaw. If Kathy weighs 132 pounds and sits on the other side, how far, in feet, from the fulcrum must she sit to have the seesaw balance? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 154 ∙ 6 = 𝑙 ∙ 132 924 = 132𝑙 𝑙= 924 =7 132 Answer: 7 Problem 18) At one end of a lever is a 320 kg weight which is 5 meters from the fulcrum. How much weight, in kg, should be placed on the other end 8 meters from the fulcrum to balance? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 320 ∙ 5 = 8 ∙ 𝑤 1600 = 8𝑤 𝑤= 1600 = 200 8 Answer: 200 17 © MathTutorDVD.com Problem 19) A person places a lever under a 180 pound rock that is 12 feet from the fulcrum. In order to lift the rock, how much force, in pounds must the person on the other end of the lever, if he is 24 feet from the fulcrum? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 ∙ 𝑤2. Substitute the numbers from this problem: 180 ∙ 12 = 24 ∙ 𝑤 2160 = 24𝑤 𝑤= 2160 = 90 24 Answer: 90 Problem 20) Where should, in meters, the fulcrum be placed under a 12 meter lever if there is a 10 kg weight on one end and a 8 kg weight on the other end in order to balance? Solution: The fulcrum is balanced with the formula 𝑙1 ∙ 𝑤1 = 𝑙2 𝑤2. Substitute the numbers from this problem: 10 ∙ 𝑙 = (12 − 𝑙)8 10𝑙 = 96 − 8𝑙 18𝑙 = 96 𝑙= Answer: 5 96 1 =5 18 3 1 3 18 © MathTutorDVD.com