Show:
Kinetic Energy
Potential Energy
Conservation of Energy
Work
Power
100
These are the two factors that affect how much kinetic energy an object has.
What are speed/velocity and mass?
100
These are the factors that affect how much gravitational potential energy an object has.
What are mass, acceleration due to gravity (g), and the height of the object?
100
During spring training batting practice last year, Red Sox superstar David Ortiz swings his bat and hits a baseball deep into center field. As the ball travels through the air, it has 4,500 Joules of kinetic energy. If at its highest point, the ball has 2,400 Joules of gravitational potential energy, then calculate the ball’s total mechanical energy using GUESS. [Hint: this one is easier than you think]
What is 6,900 Joules?
100
In which of the following scenarios is no energy being transferred from one object to another? 1. A scholar attempts to pull open a locked door. 2. An athlete throws a football 20 meters across a field. 3. A scholar blows eraser shavings off of her desk. 4. A teacher passes out a homework assignment.
What is answer choice 1. Work is a transfer of energy and requires a force and objects moving some distance.
100
Tyzamin and William were on the third floor, chatting while they walked to physics class. Suddenly, they both realized they were going to be late! Trying to avoid the L2, they both hustled down the stairs and made it to class on time. If Tyzamin and William both weigh 600 Newtons and they made it to class at exactly the same time, then who exerted more power on the way down to class? Justify your answer.
Who is neither? They both did the same amount of work (same force and distance) and they did it in the same time.
200
A 40-kilogram object moves 28 meters in only 7 seconds, thus giving it a constant speed of 4 meters per second, directed to the north. Assuming that the forces acting on the object are balanced, how much kinetic energy does it have?
What is 320 Joules? Use the formula: KE = 0.5 * m * (v*v)
200
These are the factors that affect how much spring potential energy an object has.
What are the spring constant (k) and the displacement (stretch or compression) of the spring (x)?
200
Mr. Bernard likes to play golf during the summer. He brings the golf club back, over and behind his head, and begins to quickly swing the club downwards, towards the ball. Which of the following statements describes an energy change that takes place during this time? 1. Kinetic energy increases as the club is lifted. 2. Potential energy decreases as the club is lifted. 3. Kinetic energy becomes gravitational potential ?energy as the club falls towards the ball. 4. Gravitational potential energy becomes kinetic energy as the club falls towards the ball.
What is answer choice 4.
200
Mr. Bernard grabs a television from his truck and carries it 10 meters, but then gets tired. He hands it off to Mr. Sinusas, who carries it the remaining 30 meters up the stairs. Who did more work—Mr. Bernard, or Mr. Sinusas? Defend your claim.
Who is Mr. Sinusas? He traveled the greater distance carrying the television, therefore he did more work.
200
Our school’s elevator is very powerful, especially compared to the creepy old elevator in our old school building (which was probably haunted). When Maggie first injured herself a few weeks ago, she decided to try out our school’s shiny elevator. The elevator lifted the 550-Newton Maggie from the first floor to the third floor, which is a distance of approximately 12 meters, in just 6 seconds. Calculate the power output of the elevator.
What is 1,100 Watts. Calculate the work of the elevator first and then use the P=W/t equation to solve for power.
300
What is the kinetic energy of a 1 kg pie travelling at a speed of 4 m/s? What is the kinetic energy if it is travelling at a speed of 10 m/s?
What is 8 Joules and 50 Joules?
300
Find the gravitational potential energy of a light that has a mass of 13.0 kg and is 4.8 m above the ground.
What is 624 Joules?
300
Beginning at rest, an object rolls down a frictionless hill from the top down to the ground level. If air resistance is negligible, then which of these statements is true? 1. All of the potential energy at the top becomes kinetic energy at the ground level. 2. Some of the potential energy at the top becomes kinetic energy and some becomes thermal energy at ground level. 3. All of the kinetic energy at the top becomes potential energy at ground level. 4. Some of the kinetic energy at the top becomes potential energy and thermal energy at ground level.
What is answer choice 1. There is no friction and so all of the potential energy at the top will become kinetic energy.
300
A bottle of water is at rest on a window sill when it is suddenly knocked off. The bottle, which weighs 15 Newtons, begins at rest and then falls downwards for approximately 3 seconds before hitting the ground. Assume that air resistance is negligible. If gravity does 675 Joules of work on the bottle of water while it is falling, then how far did the bottle fall?
What is 45 meters?
300
Six different bodybuilders each carry a 350-kilogram weight across an open field during competition. Some information about each bodybuilder’s effort is listed below. Bodybuilder Force Distance Traveled Average Speed A 3,500 N 60 meters 4 m/s B 3,500 N 80 meters 7 m/s C 3,500 N 71 meters 6 m/s D 3,500 N 46 meters 5 m/s E 3,500 N 39 meters 6 m/s F 3,500 N 48 meters 4 m/s Which bodybuilder exerted the most power? Defend your claim using evidence from the table above.
Who is bodybuilder B? He did the most work overall by moving the weight a greater distance, and did this work faster than the other bodybuilders.
400
A spring launcher with k = 200 N/m is compressed 0.10 meters. How much kinetic energy will a 0.05 kg ball travel when it leaves the launcher?
What is 1 Joule? Calculate the SPE from the information given. This will be equal to the kinetic energy as the marble leaves the launcher.
400
What is the SPE of a stretched spring, if k = 32 N/m and the spring is stretched to 0.45 meters?
What is 3.24 Joules? Use the equation SPE=0.5 * k * (x*x)
400
Kevin was running late to physics, so he had to jog a bit to get there on time. As he jogged, he had 1,900 Joules of kinetic energy. Kevin has a mass of 50 kilograms, and he is in the second floor hallway as he jogs to class, which puts him about 7 meters above ground level. Calculate Kevin’s total mechanical energy using GUESS.
What is 5,400 Joules?
400
Six different bodybuilders each carry a 350-kilogram weight across an open field during competition. Some information about each bodybuilder’s effort is listed below. Bodybuilder Force Distance Traveled Average Speed A 3,500 N 60 meters 4 m/s B 3,500 N 46 meters 7 m/s C 3,500 N 71 meters 6 m/s D 3,500 N 80 meters 5 m/s E 3,500 N 39 meters 6 m/s F 3,500 N 48 meters 4 m/s Which bodybuilder did the most work? Defend your claim using evidence from the table above.
Who is bodybuilder D? He carried the weight the longest distance. Using the equation W=F*d, he would have done the most work if all the bodybuilders used the same force.
400
Mr. Sinusas is pushing a 20-kilogram cart full of chromebooks down the hall. He exerts a force of 300 Newtons in order to move the cart at a constant velocity of 5 meters per second. It takes him 12 seconds to move 60 meters down the hall. Calculate the power that he used using GUESS.
What is P=1,500 Watts. First, find the work that Mr. Sinusas does and then use that value to find the power.
500
A roller coaster is at its highest point and has a mass of 400 kg and is 40 meters above the ground. When it is halfway down the track (20 meters above ground), how much kinetic energy will it have?
What is 80,000 Joules?
500
A marble is launched vertically into the air by a spring launcher with k = 200 N/m. If the mass of the marble is 0.005 kg and the spring is compressed 0.05 m, how high will the marble go?
What is 5 meters? First calculate the SPE using k and the compression (x) of the spring. This is equal to the GPE of the marble at its highest point. Using the GPE=mgh equation, solve for h using the GPE, mass, and g=10.
500
Daijah is riding her bike on a bridge from New Haven to West Haven. The bridge is 20 meters above the water below, and Daijah rides with a constant velocity of 15 meters per second. If Daijah has a mass of 40 kilograms, then determine her total mechanical energy using GUESS.
What is 12,500 Joules? Calculate the GPE and KE, and then add them together.
500
Ms. Clayton bought a new painting for her office, and wanted to hang it up on the wall. The painting weighs only 8 Newtons. She lifts the painting 2.2 meters off the ground and holds it up against the wall. She decides that’s too low, so she lifts it 0.6 meters higher and reconsiders it. Now it’s too high on the wall! She slowly lowers it 0.2 meters down, and decides that it looks perfect. How much work is done on this painting? Use GUESS to organize your work.
What is 24 Joules? Calculate the total distance that Ms. Clayton moves the painting, then use the equation W=F*d to solve.
500
Tariq lost his phone charger recently, and decided to find a creative way to replace it. Rather than just buying a normal phone charger, he created an elaborate, hamster-powered rechargeable battery using his pet hamster, Stuart. Here’s how it works: every time Stuart begins running up his hamster wheel, he spins the wheel around, which gives the wheel a certain amount of mechanical energy. This energy is captured by a semiconducting wire attached to the axis of the hamster wheel, which converts this mechanical energy into electrical energy, which in turn creates a potential difference between the two strains of the wire that can be used to re-charge his cell phone. When Tariq first tested it out, the 12-Newton Stuart began running with a constant velocity of 6 meters per second. Every 15 seconds, Stuart ran 90 meters on the wheel. Calculate the amount of power that Stuart was able to generate using GUESS.
What is 72 Watts of power? First calculate Stuart's work using W=F*d, then use the work to calculate the power that Stuart generates every 15 seconds.