The kinetic energy is transformed into gravitational potential energy on the path towards the peak of its trajectory. The groups work to answer questions. Of course, this assumes no energy is lost to air resistance, friction or any other non-conservative forces and that the arrow is shot horizontally. A Hot Wheels car starts from rest on top of an inclined plane and rolls down the incline through a loop and along a horizontal surface. a. Work, Power, Energy Worksheet . If you choose to do it again, write your First and Last name! A Hot Wheels car starts from rest on top of an inclined plane and rolls down the incline through a loop and along a horizontal surface. b. 2. There are two types of energy. Work Energy and Power Worksheet Answer Key or Eur Lex R0271 En Eur Lex. FB yg = Taf, hm Tal) Energy, Work and Power KINETIC AND POTENTIAL ENERGY WORKSHEET Name:, Determine whether the objects in the following problems have kinetic or potential energy. If the coefficient of friction between the sled and the incline is 0.109, then what will be her speed at the bottom of the inclined plane, located 8.21 m above the top of the incline. The coefficient of friction is 0.0873 along the hill and 0.527 along the horizontal surface at the bottom. Put the correct letter in the blank. The angle between the force (vertical) and the displacement (upward) vectors is 90 degrees. And if we assign the lowest position as the zero-level, then the PEf term can be canceled from the equation. Simply use the equation. It is this elevation above zero level which gives an object potential energy. This force will alter the total mechanical energy of the skier. a. A metal ball starts from rest at point A and rolls along the groove to point B. A 0.295-kg can of tomato soup is immediately hurled from the moving cart and heads towards Will N. Tasue's brand new Lexus. Assessment Chapter Review (page 39) Part A. A detailed discussion of a similar situation (the waiter and the tray of food) can be found at The Physics Classroom. 35. All About Energy Vocabulary/Answer key. (Initially the ball is at rest, KEi = 0 and cancels. A conservative force must be doing work in order for there to be a transformation of energy. List the forms of energy … 19. If you would like to take it a second time, I will average the two scores together. In each case, the PE+KE of the balls immediately after being thrown is the same (they are thrown with the same speed from the same height). d. This analysis is identical to part a except that the car has been replaced by a ball. Friction opposes motion and as such does negative work; the angle is 180 degrees. The force is upwards and the displacement is upwards. e. FALSE - Faster moving objects would have more kinetic energy than other objects of the same mass. Each picture has several types of energy associated with it. The Wnc term is dropped since it is said that no work is done by non-conservative (external) forces. Define the principle of conservation of energy and tell how it applies to a swinging pendulum. Initially, there is only PE; finally, there is neither PE nor KE; non-conservative work has been done by an applied force upon the falling object. The first method involves using the equation, where F=20.8 N, d=0.636 m, and Theta=0 degrees. Bill nye energy worksheet answers pdf. Chemical Mechanical 12. Displaying top 8 worksheets found for - Atp Energy. Since the final height is 0, PEf = 0 and cancels. FALSE - Heat or thermal energy is a non-mechanical form of energy. The algebraic rearrangement of this equation results in v = SQRT(2*KE/m). The force required to raise the car at constant speed is equivalent to the weight (m*g) of the car. Now substitutions can be made into the work-energy equation and algebraic manipulation can be performed to solve for x: 0.5•(62.9 kg)•(12.9 m/s)2 + (62.9 kg)•(9.8 m/s)•(123 m) + (72.3 N)•(505 m)•cos(180 deg) + (384 N)•(x)•cos(180 deg) = 0 J, 40. We put on a bigger engine (1111N) but the cart still moves forward 22m. Substituting and solving for vf yields 101 m/s. energy work power worksheet answer key Download Now. c. In a moment of unsupervised phun, a physics student hoists herself onto a staircase banister and accelerates down the banister. All About Energy Worksheet/Answer key. And even if v is negative, v2 will always be positive. TRUE - This is the definition of power. A 50-kg platform diver hits the water below with a kinetic energy of 5000 Joules. _____a_____1. The expressions for KE (0.5*m*v2) and PE (m*g*h) can be substituted into the equation: where m=65.8 kg, h=521 m, g=9.8 m/s/s. He uses his poles to propel himself during the entire motion. (Initially the ball is at rest, KEi = 0 and cancels. The wall does work upon the dart to stop it; this would be negative work since the force is exerted in a direction opposite the motion of the dart. ), (Note: The weight of a 25-kg object is approximately 250 N; it takes 250 N to lift the object up.). Projectile Motion, Keeping Track of Momentum - Hit and Stick, Keeping Track of Momentum - Hit and Bounce, Forces and Free-Body Diagrams in Circular Motion, I = ∆V/R Equations as a Guide to Thinking, Parallel Circuits - ∆V = I•R Calculations, Series Circuits - ∆V = I•R Calculations, Precipitation Reactions and Net Ionic Equations, Valence Shell Electron Pair Repulsion Theory, Vectors - Motion and Forces in Two Dimensions, Circular, Satellite, and Rotational Motion, Internal (i.e., Conservative) vs. b. So in this case, object A would have more kinetic energy. This worksheet allows students to identify which types of energy are associated with a variety of items and how energy is transformed between one type to another. (PEi = 0 J since the hiker starts on the ground; and KEi = KEf since the speed is constant; these two terms can be dropped from the equation since they are equal). Lifting the more massive car requires ____ work. Calculate the average upward force exerted by the ground upon Mia's fragile body. J, Object C: KE = 0.5•(1.0 kg)•(5.0 m/s)2 = ~13 J (12.5 J), Object D: KE = 0.5•(5.0 kg)•(2.0 m/s)2 = 10. d. A track is constructed by stretching a grooved and pliable material between two lab poles. The equation can be rewritten as, By substituting in expressions for kinetic and potential energy, the equation becomes. Each of the worksheets includes several questions, and each question has a corresponding answer key. b. Ignore air resistance. PSYW, There are two methods of solving this problem. e. FALSE - Whether there is envy in a physicist's heart is not for us to tell; the evil found within one's heart is often vast and mysterious ... . 6. Other renditions which adhere to these two basic principles would be considered correct. (Note there is an assumption in this problem that the collision with the Lexus chassis brings the soup can to a final rest position; This is likely not the case since a soup can typically does not become lodged inside the Lexus, but rather rebounds with a post-impact velocity. When a car skids to a stop, the work done by friction upon the car is equal to the change in kinetic energy of the car. If a non-conservative force acts upon an object, then the object will either gain or lose mechanical energy. This component is equal to the expression m•g•cos(theta) where theta is the incline angle (12.5 degrees). 1 The sine function is used to relate the angle to the initial height and the distance along the incline. You need to follow the following guidelines for the homework DUE Thursday: 1. 16. A child lifts a box up from the floor. NOTE: The next 15 questions presume that the value of g is ~10 m/s/s. It is released and falls 10.0 meters and drives a post 0.100 m into the ground. TRUE - When non-conservative forces do work upon an object, the object will either gain or lose mechanical energy. When the force and the displacement act in the same direction, positive work is done. So the analysis involves a consideration of the Wnc term. i. e. FALSE - Work is not dependent on how rapidly the force displaces an object; power is time-based and calculated by force multiplied by speed. The work-energy equation can be written as follows. Identify whether the indicated force (in boldface type) does positive work, negative work or no work. Answers will vary. Its kinetic energy is approximately ____ Joules. Friction and air resistance have a significant effect on the car. Ignore air resistance. When we use the word “work” for Remember forces are measured in Newtons (N) and Energy is measured in Jules (J). Thus, when the ball returns to its original height, their is less TME than immediately after it was thrown. This is probably best done by performing a calculation of PE and comparing the results. b. (The ball is at rest in both its initial and final states, so both KEi = 0 and KEf = 0 and cancels. Ignore the effect of friction and air resistance. FALSE - The final potential energy is calculated as PE = m•g•h = (1 kg)•(~10 m/s/s)•(1 m) = ~10 J. j. PSYW, The work energy theorem can be written as, The PEi and PEf can be dropped from the equation since they are both 0 (the height of the car is 0 m). A 510-kg roller coaster car starts at a height of 32.0 m. Assuming negligible energy losses to friction and air resistance, determine the PE, KE, and speed of the car at the various locations (A, B, C, D, and E) along the track. Use the work-energy theorem to determine the force required to stop a 988-kg car moving at a speed of 21.2 m/s if there is a distance of 45.7 m in which to stop it. Give the standard and fundamental units for a. work b. power PSYW, The work done upon an object is found with the equation, In this case, the d=6.0 m; the F=24.5 N (it takes 24.5 N of force to lift a 2.5-kg object; that's the weight of the object), and the angle between F and d (Theta) is 0 degrees. Which of the following statements are true about conservative and non-conservative forces? The Ffrict is. You need to follow the following guidelines for the homework DUE MONDAY: Spring Potential Energy & Spring Force worksheet. A 51.7-kg hiker ascends a 43.2-meter high hill at a constant speed of 1.20 m/s. The formulas are on the top of the page and the back of the reference table. So the equation becomes. Here's an example of a physical situation in which gravity first acts to do work and convert the potential energy of a soup can (and the grocery cart) into kinetic energy; then a non-conservative force - the force of the Lexus applied to the soup can - serves to change the kinetic energy of the soup can. c. A ball starts from rest at an elevated position along an inclined plane and rolls to the ground below. Or, pushing a lawn mower would be work corresponding to the physics definition. m. As the child swings, she traces out a circular arc and as such the tension (centripetal) is perpendicular to the direction of motion (tangent). The amount of work done is found by multiplying F*d*cos(Theta). 1. a. Energy is the ability to do work. The skier coasts the entire descent without using his poles; upon reaching the bottom he continues to coast to a stop; the coefficient of friction along the level surface is 0.623. Approximate the work required lift a 2.5-kg object to a height of 6.0 meters. d. TRUE - The equation states that PEgrav = m•g•h; PE is dependent upon mass. g. TRUE - This is a big principle. The skier is using his poles to propel himself so there is a non-conservative force doing work; the Wnc term does not cancel. A detailed discussion of the distance-speed squared relationship can be found at The Physics Classroom. Rank these four objects in increasing order of potential energy, beginning with the smallest. The potential energy change can be found by subtracting the initial PE (0 J) from the final PE (m*g*hf). Mia Kneezhirt jumps from a second story dorm room (h = 7.91 m) to the ground below. As you sit in your chair, there is a non-conservative force (normal force) acting upon your body. d. FALSE (sort of) - Kinetic energy depends upon mass and speed. The car has height in its initial state, so the PEi term does not cancel. The forward motion is do to the forward pushing; if the force and motion are in the same direction, then the angle is 0 degrees. During any given motion, if non-conservative forces do work upon the object, then the total mechanical energy will be changed. Applied forces, air resistance, friction forces, and tension are common examples of non-conservative forces. 11. Make sure you show work or you will not receive credit! Do consider the effects of air resistance. That's a little physics and a lot of logic - and try not to avoid the logic part by trying to memorize the answer. Note-Taking Worksheet (page 35) Refer to Teacher Outline; student answers are underlined. 44. Upon contact with the ground, she allows her 62.4-kg body to come to an abrupt stop as her center of gravity is displaced downwards a distance of 89.2 cm. Substituting and solving yields -323632 J (rounded to -324000 J). When the force and the displacement act in the same direction, positive work is done. Ignore the effect of friction and air resistance. Work and Power Worksheet Answer each question by calculating for the missing variable. (PEi and PEf = 0 J since the car is on the ground; and KEf = 0 J since the car is finally stopped). The two basic types of energy. Work is directly proportional to the displacement of the car (skidding distance) and the kinetic energy is directly related to the square of the speed (KE=0.5*m*v2). When the force and the displacement act in the opposite direction, negative work is done. e. A busy spider hangs motionless from a silk thread, supported by the tension in the thread. If we assign the ground below the cliff to be the zero-level of potential energy, then the PEf term can be canceled from the equation. She is at rest on top of a hill with a height of 92.6 m and an incline angle of 19.2 degrees. 3. At this same starting height, the PE is the same as before. Work involves a force acting upon an object to cause a displacement. 21. A metal ball starts from rest at point A and rolls to point B. Friction and air resistance have a significant effect on the car. A baseball player catches a 163-gram baseball which is moving horizontally at a speed of 39.8 m/s. Ignore air resistance. The force of friction is related to the normal force (= m•g) and the coefficient of friction (0.728). • Describe how human society uses energy resources. How much work has been done to the block? A 1200 kg car and a 2400 kg car are lifted to the same height at a constant speed in a auto service station. A skier at the top of the mountain(a) Kinetic Energy ___b___2. Upon reaching the vertical, the string hits a barrier and a new pivot point is established as the bob continues in motion along an upward trajectory. The situation is depicted at the right. - Thermal Energy (better as known as heat) - Kinetic Energy (better known as movement) - Gravitational Potential Energy (the energy released when you jump off a wall, for example) James Joule's work was rewarded by naming the units used to measure energy after him. d. The force of friction acts upon a baseball player as he slides into third base. f. In baseball, the catcher exerts an abrupt applied force upon the ball to stop it in the catcher's mitt. d. FALSE- If a non-conservative force does work upon an object, then the total mechanical energy of that object is changed. Note the bottom answers are slightly off due to rounding and choice of speed/height. where F=7160 N, d=45.2 m, and Theta=180 degrees (the force is in the opposite direction as the displacement). Determine the impact speed of the ball when it strikes the ground. Continue reading. The presence of air resistance (a non-conservative force) does a little work and so one might notice a very slight change in mechanical energy. The difference in potential energy must be made up for in the form of kinetic energy. The formulas are on the top of the page and the back of the reference table. Now substitutions can be made into the earlier stated equation and algebra manipulations can be performed to determine the final speed. He skis down the hill into the valley and up a second smaller hill. How far will he coast along the level area at the bottom of the slope? Part 1. So. A machine can do a lot of work but if it fails to do it rapidly, then it is not necessarily powerful. c. The force is backwards and the displacement is forwards. In fact two machines can do the same task (and therefore the same work), yet they can have drastically different power ratings. The rate at which energy is used (i.e., power) in raising the 50.0 kg crate is ____ as the rate at which energy is used to lift the 25.0 kg crate. Since the final height is 0, PEf = 0 and cancels. c. The acceleration of the car can be found using Newton's second law of motion: Fnet = m*a. The slope has an angle of 14.1 degrees and a coefficient of friction of 0.121. Negative work is done when there is a component of force opposite the direction of motion. The diagram at the right depicts the physical situation. Which of the following statements are true about potential energy? You can add normal force to the list as well. Answers will vary. This sort of energy includes an atom’s nucleus. When the force and the displacement act in the same direction, positive work is done. Bending of a wave as it passes around a barrier. b. Some of the worksheets for this concept are Work and machines answer key, Simple machines, Simple machines work, Simple machines, Name simple machines work section 83, Name simple machines, Simple machines, Teacher guide answers continued. Either this additional distance must be included in the PE term or it is assumed that Mia's landing involves somewhat of a spring action whereby she bends her knees to lower her body and then straightens up to an upright position - similar to the landing of an Olympic gymnast. Substituting 500 N for m*g (500 N is the weight of the diver, not the mass) and 10 m for h will yield the answer of 5000 J. FALSE - Kinetic energy depends upon the speed of the object; potential energy depends upon the position of the object. The original equation then simplifies to, Expressions for potential energy and work can be substituted into this equation to change its form to. (A kinematic equation could be also used to find the initial velocity.). 1. 9+ Work And Energy Worksheet Key. It contains 2 digestive system worksheets covering the main organs a wordsearch with all life system key words matching activity that is an overview of all life systemthan. h. This is a straightforward question; no tricks here. It would however be possible that work is not done by a non-conservative force and there be no transformation of energy at all; i.e., the object remains at rest. J of work, a small object is lifted from the ground floor to the third floor of a tall building in 20.0 seconds. d. TRUE - An equation for computing work in constant speed situations is P=F•v. So the above equation becomes. A Guide to Work, Energy and Power Teaching Approach Work, Energy and Power is a topic which comprise of three concepts which are very closely related – work and energy and power. Define with an equation and in words: a. kinetic energy b. potential energy c. work d. power 2. Ignore the effect of air resistance. How far will the car skid with locked brakes if it is traveling at 120. km/hr?