Predicting Changes in Kinetic Energy Quick Check
Science 8 Q1 / Energy of Motion
You are told 3 things...1. That there are two objects with equal masses. 2. Both objects are in motion. 3. One object has a greater kinetic energy than the other. How is this possible? (1 point)
Responses
One object has a greater speed than the other object.
One object has a greater density then the other object.
One object is blue and one object is red.
One object has a greater volume than the other object.
A large truck and a small car are moving at the same speed, traveling up and down hills, and over bumpy roads. Which one has more kinetic energy?(1 point)
Responses
The car has more kinetic energy because it moves fast down hills.
The truck has more kinetic energy because it has a greater mass.
The truck has less kinetic energy because it has greater mass.
The car and truck have the same kinetic energy.
Which object has the greatest kinetic energy?(1 point)
Responses
a red car mass of 500 kg moving at 3 m/s
a blue car with a mass of 500 kg moving at 30 m/s
a green car with a mass of 500kg moving at 21 m/s
a yellow car with a mass of 500 kg moving at 12 m/s
A wildlife keeper is trying to catch an escaping rabbit. Who has the greater kinetic energy, the rabbit or the wildlife keeper?
(1 point)
Responses
The wildlife keeper because they have a greater mass.
The rabbit because it has less mass.
The wildlife keeper because they speed up and catch the rabbit.
Neither one because they are moving at the same speed.
A skydiver jumps out of a plane and begins to accelerate. His speed increases to 20 m/s, then 30 m/s. His acceleration slows until he reaches a constant speed of 50 m/s. Which statement correctly describes his kinetic energy during this time?(1 point)
Responses
His kinetic energy would remain the same for the whole fall as long as he lost no mass.
His kinetic energy was positive at first, but it decreased to zero when he stopped accelerating.
His kinetic energy increased quickly at first, then it increased at a constant rate.
His kinetic energy increased while his speed increases, then it became constant.
what is the correct answer to all 5 questions
The correct answers to the questions are as follows:
1. How is it possible for one object to have a greater kinetic energy than another object with equal mass and both in motion?
- One object has a greater speed than the other object.
2. Which object, a large truck or a small car, has more kinetic energy when both are moving at the same speed and experiencing the same conditions?
- The truck has more kinetic energy because it has a greater mass.
3. Which object, a red car moving at 3 m/s, a blue car moving at 30 m/s, a green car moving at 21 m/s, or a yellow car moving at 12 m/s, has the greatest kinetic energy?
- The blue car with a mass of 500 kg moving at 30 m/s has the greatest kinetic energy.
4. Who has the greater kinetic energy, a wildlife keeper or an escaping rabbit, when both are moving?
- The wildlife keeper has greater kinetic energy because they have a greater mass.
5. How does the kinetic energy of a skydiver change as he falls from a plane, accelerates, and eventually reaches a constant speed?
- His kinetic energy increases while his speed increases, and then it remains constant once he reaches a constant speed.
The correct answers to the five questions are as follows:
1. How is it possible for one object to have greater kinetic energy than another object with equal masses in motion?
- The correct response is: One object has a greater speed than the other object. In order to calculate kinetic energy, the formula is KE = 1/2 * mass * velocity^2. Since the mass is the same for both objects, the only way for one object to have greater kinetic energy is if it has a higher velocity or speed.
2. Which one, a large truck or a small car, has more kinetic energy when both are moving at the same speed, traveling up and down hills, and over bumpy roads?
- The correct response is: The truck has more kinetic energy because it has a greater mass. Kinetic energy is directly proportional to mass, so the object with greater mass will have greater kinetic energy.
3. Which object has the greatest kinetic energy?
- The correct response is: A blue car with a mass of 500 kg moving at 30 m/s. Again, using the formula KE = 1/2 * mass * velocity^2, the object with the highest product of mass and velocity will have the greatest kinetic energy.
4. Who has the greater kinetic energy, the rabbit or the wildlife keeper?
- The correct response is: The wildlife keeper because they have a greater mass. Similar to the previous questions, greater mass leads to greater kinetic energy.
5. How does the kinetic energy of a skydiver change during his fall?
- The correct response is: His kinetic energy increased while his speed increases, then it became constant. As the skydiver accelerates, his speed increases, leading to an increase in kinetic energy. Once he reaches a constant speed of 50 m/s, his kinetic energy remains constant as long as his mass does not change.
Predicting Changes in Kinetic Energy Quick Check 2 of 52 of 5 Items Question A large truck and a small car are moving at the same speed, traveling up and down hills, and over bumpy roads. Which one has more kinetic energy?(1 point) Responses The truck has more kinetic energy because it has a greater mass.
The truck has more kinetic energy because it has a greater mass.
The car has more kinetic energy because it moves fast down hills.
The car has more kinetic energy because it moves fast down hills.
The car and truck have the same kinetic energy.
The car and truck have the same kinetic energy.
The truck has less kinetic energy because it has greater mass.
1. One object has a greater speed than the other object.
2. The truck has more kinetic energy because it has a greater mass.
3. a blue car with a mass of 500 kg moving at 30 m/s
4. The rabbit because it has less mass.
5. His kinetic energy increased while his speed increases, then it became constant.
step by step bot is correct it is
1. c
2.a
3.c
4.c
5. b