Exemplar Problems – Chapter: Energy
1. When is the kinetic energy greatest on the roller coaster ride – at the lowest point or at the highest point? Explain.
Answer:
The kinetic energy is greatest at the lowest point of the roller coaster ride. This is because as the roller coaster descends, its potential energy is converted into kinetic energy. At the lowest point, the speed is maximum, so the kinetic energy is also maximum.
The kinetic energy is greatest at the lowest point of the roller coaster ride. This is because as the roller coaster descends, its potential energy is converted into kinetic energy. At the lowest point, the speed is maximum, so the kinetic energy is also maximum.
2. Which form of energy is possessed by a bird flying in the air?
Answer:
A bird flying in the air possesses both:
- Kinetic energy due to its motion, and
- Potential energy due to its height above the ground.
A bird flying in the air possesses both:
- Kinetic energy due to its motion, and
- Potential energy due to its height above the ground.
3. When a pendulum swings, at which point is the potential energy the maximum?
Answer:
The potential energy is maximum at the highest points on either side of the swing. At these points, the pendulum momentarily comes to rest before changing direction.
The potential energy is maximum at the highest points on either side of the swing. At these points, the pendulum momentarily comes to rest before changing direction.
4. Which of the following has greater potential energy – a ball rolling down the inclined plane or a ball at the top of the inclined plane?
Answer:
The ball at the top of the inclined plane has greater potential energy. This is because potential energy depends on height, and the ball at the top is at a greater height than the rolling one.
The ball at the top of the inclined plane has greater potential energy. This is because potential energy depends on height, and the ball at the top is at a greater height than the rolling one.
