Physics: Potential and Kinetic Energy in Daily Life
Identifying stored energy and motion energy in everyday situations
Physics: Potential and Kinetic Energy in Daily Life
Identifying stored energy and motion energy in everyday situations
Physics - Grade 6-8
- 1
A skateboarder waits at the top of a ramp before rolling down. Identify the main type of energy the skateboarder has at the top of the ramp and explain why.
Think about energy that is stored because of height.
At the top of the ramp, the skateboarder has mostly gravitational potential energy because the skateboarder is raised above the ground and has stored energy due to position. - 2
A soccer ball is kicked across a field. Identify the main type of energy the moving ball has and explain why.
The moving soccer ball has kinetic energy because it is in motion across the field. - 3
A book sits on the top shelf of a bookcase. How would the book's gravitational potential energy change if it were moved to a lower shelf?
Higher objects have more gravitational potential energy if their mass stays the same.
The book's gravitational potential energy would decrease because it would be closer to the ground and have less stored energy due to height. - 4
A stretched rubber band is held between your fingers. What type of potential energy does it have, and what happens to that energy when you let go?
The stretched rubber band has elastic potential energy. When you let go, much of that stored energy changes into kinetic energy as the rubber band moves. - 5
A student drops a pencil from a desk. Describe how the pencil's potential energy and kinetic energy change as it falls.
During a fall, height decreases while speed increases.
As the pencil falls, its gravitational potential energy decreases because it loses height. Its kinetic energy increases because it speeds up as it moves downward. - 6
Two identical water bottles are sitting on shelves. Bottle A is on a shelf 1 meter above the floor. Bottle B is on a shelf 2 meters above the floor. Which bottle has more gravitational potential energy, and why?
Bottle B has more gravitational potential energy because it is higher above the floor, and both bottles have the same mass. - 7
A bicyclist pedals faster on a flat road. How does the bicyclist's kinetic energy change as speed increases?
More speed means more energy of motion.
The bicyclist's kinetic energy increases because kinetic energy depends on motion, and a faster moving object has more kinetic energy. - 8
A roller coaster car is moving down the first big hill. Explain how energy is changing from the top of the hill to the bottom.
At the top, the roller coaster car has a lot of gravitational potential energy. As it moves down the hill, that energy changes into kinetic energy, so the car speeds up. - 9
A lunchbox and a backpack are both placed on the same table. The backpack has more mass than the lunchbox. Which object has more gravitational potential energy on the table, and why?
Gravitational potential energy depends on both mass and height.
The backpack has more gravitational potential energy because it has more mass and both objects are at the same height. - 10
A car is parked at the top of a steep driveway. Later, it rolls down the driveway. Identify the main energy type before it starts moving and the main energy type while it is rolling.
Before it starts moving, the car has mostly gravitational potential energy because of its height on the driveway. While it is rolling, it has kinetic energy because it is moving. - 11
A child pulls a toy car backward and lets it go so it races forward. The toy car has a spring inside. What energy changes happen in the toy car?
A stretched or compressed spring stores elastic potential energy.
Pulling the toy car backward stores elastic potential energy in the spring. When the car is released, the stored energy changes into kinetic energy as the car moves forward. - 12
A basketball is held above the floor and then dropped. At what point does it have the greatest gravitational potential energy: when it is held high, halfway down, or just before it hits the floor? Explain your answer.
The basketball has the greatest gravitational potential energy when it is held high because that is when it has the greatest height above the floor. - 13
A bowling ball and a tennis ball roll at the same speed. Which one has more kinetic energy, and why?
Kinetic energy depends on both mass and speed.
The bowling ball has more kinetic energy because it has more mass, and both balls are moving at the same speed. - 14
A phone is charging on a desk, then it falls off the desk. Explain why the phone has potential energy before it falls and kinetic energy while it falls.
Before it falls, the phone has gravitational potential energy because it is above the floor. While it falls, it has kinetic energy because it is moving downward. - 15
Write your own daily life example in which potential energy changes into kinetic energy. Identify the object and explain the energy change.
Choose an example where an object starts with stored energy and then begins moving.
One possible answer is a sled at the top of a snowy hill. The sled has gravitational potential energy at the top, and that energy changes into kinetic energy as the sled slides down the hill.