Question

1. when a stretched spring is released, its potential energy becomes:

a) kinetic energy
b) heat energy
c) electrical energy
d) nuclear energy

1. at the highest point of a swing, the swing has mostly:

a) kinetic energy
b) potential energy
c) chemical energy
d) electrical energy

1. at the lowest point of a swing, the swing has mostly:

a) kinetic energy
b) potential energy
c) thermal energy
d) nuclear energy

1. a rock at the edge of a cliff has:

a) high kinetic energy
b) high potential energy
c) no energy
d) heat energy only

1. as a ball falls, its:

a) potential energy decreases, kinetic energy increases
b) potential energy increases, kinetic energy decreases
c) both energies increase
d) both energies decrease

1. which example shows energy being transformed from potential to kinetic?

a) a diver jumping off a diving board
b) a runner stretching before a race
c) a student sitting at a desk
d) a car parked in the driveway

1. which example shows energy being transformed from kinetic to potential?

a) a child climbing a slide ladder
b) a dog running across a yard
c) a plane flying at constant altitude
d) a fish swimming forward

1. a ball thrown upward slows down because:

a) kinetic energy transforms into potential energy
b) potential energy transforms into heat energy
c) energy is destroyed
d) energy disappears

1. when you hold a stretched bow with an arrow, the arrow has:

a) kinetic energy
b) potential energy
c) thermal energy
d) no energy

Explanation:

• Question 9: According to the law of conservation of energy, when a stretched spring is released, its elastic potential energy is converted into kinetic energy as it moves.
• Question 10: At the highest point of a swing, the swing is momentarily at rest (zero velocity for an instant), so kinetic energy is near - zero. But it has a height, so it has gravitational potential energy.
• Question 11: At the lowest point of a swing, the height is minimum (so potential energy is minimum) and the velocity is maximum (so kinetic energy is maximum).
• Question 12: A rock at the edge of a cliff has height (\(h>0\)) relative to the ground. Using the formula for gravitational potential energy \(U = mgh\) (\(m\) is mass, \(g\) is acceleration due to gravity, \(h\) is height), it has high potential energy. Since it is at rest (assuming no wind - induced motion etc.), kinetic energy is near - zero.
• Question 13: As a ball falls, its height (\(h\)) decreases. Using \(U=mgh\), potential energy decreases. And as it falls, its velocity (\(v\)) increases. Using \(K=\frac{1}{2}mv^{2}\), kinetic energy increases.
• Question 14: A diver jumping off a diving board: before jumping, the diver has potential energy (due to height). As the diver jumps, this potential energy is converted into kinetic energy (as the diver moves downwards).
• Question 15: A child climbing a slide ladder: the child is doing work against gravity. As the child climbs (increases height \(h\)), kinetic energy (from the child's muscular movements) is converted into gravitational potential energy (\(U = mgh\)).
• Question 16: A ball thrown upward: as it moves up, its velocity (\(v\)) decreases (so kinetic energy \(K=\frac{1}{2}mv^{2}\) decreases) and its height (\(h\)) increases (so potential energy \(U = mgh\) increases). So kinetic energy transforms into potential energy.
• Question 17: When you hold a stretched bow with an arrow, the bow has elastic potential energy (due to its deformation). This potential energy can be transferred to the arrow when the bow is released.

Answer:

1. A. Kinetic energy
2. B. Potential energy
3. A. Kinetic energy
4. B. High potential energy
5. A. Potential energy decreases, kinetic energy increases
6. A. A diver jumping off a diving board
7. A. A child climbing a slide ladder
8. A. Kinetic energy transforms into potential energy
9. B. Potential energy