Learning Activity Sheet general Physics PDF

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This is a a Learning Activity Sheet in General Physics...

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General Physics 1 – Grade 12 Learning Activity Sheets Quarter 1

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Published by the Department of Education – Schools Division of Tacloban City Schools Division Superintendent: Mariza S. Magan Assistant Schools Division Superintendent: Edgar Y. Tenasas Development Team of the Activity Sheet

Writer: Rosemarie B. Balute Angellie G. Mabutin Evaluator: Danilo M. Macapugas Jr. Management Team: CID Chief: Mark Chester Anthony G. Tamayo Division EPS of LRMS: Gretel Laura M. Cadiong Division Learning Area EPS: Arnulfo Q. Banzon

Department of Education - Region No. VIII – Schools Division Office of Tacloban City Office Address:

Real St., Tacloban City

NAME: _________________________________ GRADE & SECTION: ___________ LEARNING ACTIVITY SHEET No.

7

DATE ANSWERED:

POWER As you start this activity it is important to have understanding about the topic. This section will give you an overview about the concepts to help you in learning the lesson.

LET’S KICK IT OFF!

In many situations, the time it takes to do work is just as important as the amount of work that is done. Considering there are two automobiles which are identical in all aspects (e.g., both have the same mass), except that one has a “souped-up” (modified) engine. The car with the souped-up engine can go from 0 to 27 m/s (60 mph) in 4 seconds, while the other car requires 8 seconds to achieve the same speed. Each engine does work in accelerating its car, but one does it more quickly. Where cars are concerned, we associate the quicker performance with an engine that has a larger horsepower rating.

ARE YOU TAKING IT?

Based on the passage above, which car do you think exhibits greater power in terms of its horsepower rating? Justify your answer ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ _______________________________________________________________________.

HERE HOW IT IS!

POWER Power is the average rate at which work W is done, and it is obtained by dividing W by the time t required to perform the work:

𝑃=

𝑊𝑜𝑟𝑘 𝑊 = 𝑇𝑖𝑚𝑒 𝑡

SI Unit of Power: joule/s = watt (W)

The definition of power presented above involves work. However, the work– energy theorem relates the work done by a net external force to the change in the energy of the object. Therefore, we can also define power as the rate at which the energy is changing, or the change in energy divided by the time during which the change occurs:

𝑃=

𝑐ℎ𝑎𝑛𝑔𝑒 𝑖𝑛 𝐸𝑛𝑒𝑟𝑔𝑦 ∆𝐸 = 𝑇𝑖𝑚𝑒 𝑡

Since work, energy, and time are scalars, power is also a scalar. The unit in which power is expressed is that of work divided by time, or a joule per second in SI units. One joule per second is called a watt (W), in honor of James Watt (1736–1819), developer of the steam engine. The Principle of Conservation of Energy Energy can neither be created nor destroyed, but can only be converted from one form to another.

NOW YOU DO IT!

Problem Solving 1. A person is making homemade ice cream. She exerts a force of magnitude 22 N on the free end of the crank handle on the ice-cream maker, and this end moves on a circular path of radius 0.28 m. The force is always applied parallel to the motion of the handle. If the handle is turned once every 1.3 s, what is the average power being expended? (HINT: Calculate first the work)

ACE IT!

ASSESSMENT IDENTIFICATION __________________1. It is the SI unit for power which was named after the scientist in honor for the discovery of steam engine. __________________2. It is define as the work done by an object over a period of time. __________________3. This principle states “Energy can neither be created nor destroyed, but can only be converted from one form to another”. __________________4. Engine A has a greater power rating than engine B. Describe correctly the abilities of these engines to do work. __________________5. Is it correct to conclude that one engine is doing twice the work that another is doing just because it is generating twice the power?

NAME: _________________________________ GRADE & SECTION: ___________ LEARNING ACTIVITY SHEET No. 8

DATE ANSWERED:

MOMENTUM AND IMPULSE LET’S KICK IT OFF!

Directions: Analyze and describe the image found below then answer the questions that follow.

(www.skysports.com)

__________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________

ARE YOU TAKING IT?

Directions: After studying the image above, answer the questions below: 1. 2. 3. 4.

What is momentum? From the image above, Which player has the largest kinetic energy? When and how does change in momentum occur? Using the concepts of momentum, work, and energy, explain how a rugby player can be more effective with his feet on the ground. 5. Under what circumstances is momentum conserved?

HERE HOW IT IS! Notes to Ponder Momentum and Impulse Momentum is used to quantitatively measure an object’s motion. It is equivalent to the product of one’s mass and velocity. Expressing the definition mathematically, 𝒑 = 𝒎𝒗 Where 𝑝 is the momentum in 𝑘𝑔 ∙ 𝑚/𝑠, m is the mass in kg and v is the velocity of the object in m/s. Every moving object has momentum. It may be small or large depending on their mass and velocity. Example 1: Calculate the momentum of a volleyball which has a mass of 0.5 kg and is moving at a rate of 40 m/s to the right. Given: m= 0.5 kg v= 40 m/s right p=? Solution: 𝑝 = 𝑚𝑣 = (0.5 𝑘𝑔) (40 𝑚/𝑠) = 20 𝒌𝒈 ∙ 𝒎/ (right)

When an object collided to another object, it experiences a force for a specific amount of time that results in change of momentum. The change in momentum can be expressed using the 2nd Law of Newton, F= ma Expressing mathematically the acceleration,

𝑎=

𝒗−𝒗𝒐 ∆𝒕

Substituting the value of a in 2nd Law of Newton,

F =m (

𝒗−𝒗𝒐 ∆𝒕

)

Rearranging the equation, 𝑭∆𝒕 = 𝒎𝒗 – 𝒎𝒗𝟎 The right side of the equation indicates a change in momentum so the equation can also be written as: 𝑭∆𝒕 = ∆𝒑 The equation above represents the force applied and the time as two important factors affecting change in momentum. From the left side of the equation, the product of force applied, and the time is known as Impulse. Where Impulse is in - 𝑁 − 𝑠 while change in momentum is in 𝑘𝑔 ∙ 𝑚/𝑠. Example 2: A ball with a mass of 0.06 kg is initially at rest and suddenly subjected to an impulse that causes it to move with a velocity of 50 m/s. If the ball and net are in contact for 𝒙 10−3 𝒔 , what average net force acts on the ball? Given: m= 0.06 kg v= 50 m/s t= 𝟓 𝒙 10−3 𝒔 f=? Solution: 𝐹∆𝑡 = 𝑚𝑣 − 𝑚𝑣0 𝒎𝒗 − 𝒎𝒗𝒐 F= F=

∆𝒕 𝒎 𝟓𝟎𝒎 (𝟎.𝟎𝟔 𝒌𝒈) ( ) ) − (𝟎.𝟎𝟔 𝒌𝒈) (𝟎

= 𝟔𝟎𝟎 𝑵

𝒔

𝟓 𝒙 10−3 𝒔

𝒔

Law of Conservation of Momentum Law of Conservation of Momentum states that a total momentum before collision is equal to total momentum after collision. The mathematical expression for this statement can be presented as, 𝑝1 + 𝑝2 = 𝑝’1 + 𝑝’2 𝒎𝟏 𝒎𝟏𝒗𝟏 𝒗𝟏 + 𝒎𝟐 𝒎𝟐𝒗 𝒗𝟐 = 𝒎𝟏𝒗’𝟏 𝟏 + 𝒎𝟐 𝒗’𝟐 𝟐 Collision Collision is an interaction between two or more objects that come in contact with each other that results in exchange of impulse and momentum. Since collision is a short duration encounter between two or more bodies, the impulse provided by the external forces like friction is negligible. The momentum of the system is conserved when considering colliding objects as one system. Types of Collision A. Elastic collision, the objects move separately, and both of the objects retain their distinct mass state after collision. Both momentum and kinetic energy are conserved during an elastic collision. Throwing a ball on the ground and bounces back to your hand and also playing billiards are examples of elastic collision. B. Inelastic collision, if two objects stick together and move as one after collision, it is said to be completely inelastic collision or perfectly inelastic collision. Two colliding balls of putty sticking together or two cars joining together when they collide are examples of completely inelastic collision.

NOW YOU DO IT!

Activity 1 Direction: Solve the following problems about Momentum and Impulse. Make sure to show your solution. Use separate sheet of paper. 1. Calculate the momentum of a 1.60 x 103 kg car traveling at 20.0 m/s. 2. What is the velocity of a bicycle with a mass of 5 kg and momentum Of 20 kg · m/s moving in the forward direction? 3. Compare the momentum of a 2000 kg car moving at 30 m/s with a

5000 kg truck moving at 12 m/s. 4. A 1200 kg train traveling at 20.0 m/s speeds up to 30.0 m/s. What is the impulse experienced by the train ? 5. In a billiard table, a ball of mass weighing 250 g rolls with a velocity of 2.5 m/s and rebounds back at 2.5 m/s. Calculate the following: a. change in momentum b. impulse experienced by the ball Activity 2 Objectives: • Investigate the factors affecting the momentum of an object • Investigate the relation between Impulse and Momentum Materials needed: 1 toy truck that can be loaded 0.50 m wooden/cardboard plane A piece of wood A piece of foam 5 books Set of weights or things that can be put in the toy truck

Shoe box 3 eggs A piece of newspaper A piece of clothe Metersticks/ruler

Estimated time frame: 30 minutes

A. Effect of Mass on Momentum and Distance Traveled 1. Determine the mass of the toy truck. 2. Incline the plane by placing a book under it on one end. 3. Position the truck at the top of the plane and release it. 4. Measure the distance the truck traveled before it stops. You may use the end of the truck as your reference in measuring distance and height. 5. Repeat steps 3 to 4 by adding 100 g of weights or anything that can be put in toy truck each time until the total mass added on the truck is 500g. 6. Compare the speed of the toy truck at the bottom of the inclined plane using 𝑣 = √2𝑔ℎ where h is the height of the inclined plane. 7. Compute the momentum of the toy truck and mass added.

Mass of toy truck= ___________ speed of the bottom of the incline=________ Total mass (kg)

Distance traveled (m)

Momentum (kg. m/s)

Activity 3 Impulse and Momentum 1. Put the wood inside the shoebox. 2. From a height of 1.0 m, drop an egg so that it will land in the wood inside the shoebox. Did the egg break? 3. Repeat the procedure replacing the wood by foam and newspaper, one after the other. MATERIAL Newspaper

Wood

Clothe

Foam

OBSERVATION

ACE IT! Assessment

MULTIPLE CHOICE Directions: Write the corresponding answer in the space provided for each item. 1. Among the three vehicles, which has the greatest momentum? A. bicycle B. jeepney C. motorcycle D. cannot be determined 2. Among the three vehicles, which has the least momentum? A. bicycle B. jeepney C. motorcycle D. cannot be determined 3. Two identical jeepneys are travelling along San Fernando City. Which of the two jeepneys would have a greater momentum? A. faster jeepney B. slower jeepney C. both have the same momentum D. cannot be determined 4. Which quantity is always conserved in all types of collisions? A. kinetic energy B. momentum C. mechanical energy D. potential energy 5. What happens to the momentum of an object when its velocity is doubled and its mass remains constant? A. doubled B. increased four times C. reduced to one-half D. remains the same...