WORK Least Mastered Skills v Identifying whethere is

WORK

Least Mastered Skills v Identifying whethere is work done or no work done v Solve problems involving work

Overview… Work results when a force acts upon an object to cause a displacement (or a motion). Force Displacement Mathematical Representation Work = Force • Displacement W = F • d

Look! The cart moves in the same direction with the force I applied!! Applied Force Motion of Cart Remember! Work is done if the direction of the force is the same with the direction of motion of an object.

This is so hard to move. Arghh!!. . No Motion Applied Force Remember! No work is done when the object do not move even you applied great amount of force.

My Father is stronger because he carries two bags of groceries. Displacement Applied Force Remember! No work is done if the force you exert does not make the object move in the same direction as the force you exerted.

Calculating Work is defined as the product of force applied to an object to the distance travelled by the object or simply Work = Force x displacement W = F x d Sample Problem # 1 Abraham travels everyday using the car that his mother gave him. One day, his car runs out of gasoline so he doesn’t have a choice but to push it. If he pushes the car with a force of 150 Newton along the 23 meters road, what will be the amount of his work done? Step # 1: Identify the given. Given: W = ______ F = 150 N d = 23 m

Step # 2: Write the formula. W=Fxd Step # 3: Substitute the given values. W=Fxd W = 150 N x 23 m W = 3450 N. m or 3450 J Sample Problem # 2 Xailee works in her garden every morning. One day, she load all unwanted plants in her cart to make her garden more fantastic. She pushed the cart with a force of 10 Newton. If the cart travels 77 meters, how much work did Xailee does? Given: Solution W =_____W = F x d F = 10 NW = 10 N x 77 m d = 77 m. W = 770 J

Direction: Tell whether work is done or no work is done on the following figure. 1. ________________________ 2. ________________________ 3. ________________________ 4. ________________________

Direction: Solve the following. Show your complete solution. 1. Tom pushes a box with a force of 33 Newton along the 17 meters aisle inside their house. How much work is done by Tom? _________________________________________________________________________ ___________________ 2. Jack and Jill went up the hill to get a pail of water. Jack went to the well 48 meters deep and pulled the pail with a force of 72 Newton. What is the amount of his work done? _________________________________________________________________________ ___________________

3. Winnie the Pooh is struggling to get honey. He then pulled the branch of tree exerting a force of 120 Newton. The branch moved towards Winnie the Pooh whose 7 meters away. What was his work done? __________________________________________________________________ _________________________________

Direction: Identify the direction of force and direction of motion on the following figure by putting an arrow. Write if work is done or work is not done on the space provided. 1. 3. 2. 4.

5. 6. 7. 8.

Direction: Solve the following word problems. Show complete solution. 1. Jessica is a football player. She has a strong pair of feet. In the game, Jessica kicked the ball with a force of 150 Newton and she made a work done of 3115 J. How far did the ball travelled? _________________________________________________________________________ _________________________________________________________________________ ________________________________

2. Marcus works as an engineer in a big real estate company in Manila. While he is in the site, one of his foremen asked for his help to reach a tool and give it to him. He then lifts the cutting tool 7 meters high. If Marcus has an amount of 218 J work done that day, how much force did he exerted? ________________________________________________________________________ ________________________________________________________________________ ________________________________ 3. Pinky loves to buy groceries for her family every weekend. She make it sure that they have enough stock for the whole week. She loaded the shopping cart with canned goods, veggies, fruits, and soda. Walking along 23 meters store, she pushes her cart with 15 Newton force. What will be the amount of work done by Pinky?

A. Direction: Draw a smiling face if there is work done and a sad face if there is no work done in the following situations. Draw your answer on the space provided before the number. _______ 1. Lina selling fruits. _______ 2. Driving a bicycle _______ 3. Lifting the cabinet to second floor of the house _______ 4. Pulling the chair 1 meter backwards _______ 5. Pushing the car along the 3 meters bridge _______ 6. Pushing the school wall _______ 7. Pushing your classmate inside the room _______ 8. Trimming the plants in your school garden _______ 9. Washing the dishes _______ 10. Lifting the weights in the gym B. Direction. Cite five (5) examples of your daily activities having a work done. 1. _______________________ 2. _______________________ 3. _______________________ 4. _______________________ 5. _______________________

A. Direction: Draw four (4) activities/situations where you did work. Place your work of art inside the boxes.

1. 2. 3. 4. 5. 6. 7. 8. Activity Card # 1 no work is done work is done no work is done

Activity Card # 2 1. Given: W= F = 33 N d = 17 m Solution: 2. Given: W= F = 72 N d = 48 m Solution: 3. Given: W= F = 120 N d=7 m Solution: Awesome!!! W=Fxd W = 33 N x 17 m W = 561 N. m or 561 J W=Fxd W = 72 N x 48 m W = 3456 N. m or 3456 J W=Fxd W = 120 N x 7 m W = 840 N. m or 840 J

1. 2. Work is done 3. 4. Work is done 5. Work is done 6. Work is done 7. Work is done 8. Work is done No Work is done

1. Given: W = 3115 J F = 150 N d= d=W d Solution: 2. Given: W = 218 J F = d = 7 m Solution: 3. Given: W = F = 15 N d = 23 m Solution: W=Fxd F F 150 N d = 20. 77 m d=W d d = 3115 N. m F = W W = F x d d d d F = 218 N. m F = W 7 m d F = 31. 14 N W = F x d W = 15 N x 23 m W = 345 J

ENRICHMENT CARD # 1 A. _______ 1. Lina selling fruits. _______ 2. Driving a bicycle _______ 3. Lifting the cabinet to second floor of the house _______ 4. Pulling the chair 1 meter backwards _______ 5. Pushing the car along the 3 meters bridge _______ 6. Pushing the school wall _______ 7. Dribbling the ball. _______ 8. Trimming the plants in your school garden _______ 9. Washing the dishes _______ 10. Lifting the weights in the gym B. 1. Picking a bottle from the ground to put above the table. 6 2. Pushing the cart inside the supermarket. 3. Lifting a box to put above the cabinet. 4. Hitting the ball to go to the other team. 5. Pushing the stroller in the 20 meters garden.

A. ENRICHMENT CARD # 2 A.

I want to learn more about work… I should find another evidence… • Department of Education. (2013). Science – Grade 8 Learner’s Material, First Edition. Pasig City. Author. www. wikipedia. com • Paul G. H. , Conceptual Physics Eighth Edition. Addison – Wesley Longman Ernest P. M,

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