Determine whether each statement below is true or false.
The force necessary to lift an object is its mass times g.
Kinetic energy is the energy of motion.
Stopping distance is doubled, if speed is doubled.
Work is the product of force and time.
A joule is a newton times a second.
Work is done to lift an object in the classroom.
1. True
2. True
3. False.
4. False
5. False
6. True
To determine whether each statement is true or false, let's break down each statement and explain how to find the answer:
1. The force necessary to lift an object is its mass times g.
To determine if this statement is true or false, we need to know the definition of force and the role of gravity. According to Newton's second law of motion, force (F) is equal to mass (m) multiplied by acceleration (a). In the case of lifting an object, the acceleration due to gravity (g) is the relevant acceleration factor. So, the equation for force (F) would be F = m * g. Therefore, the statement is TRUE.
2. Kinetic energy is the energy of motion.
To determine if this statement is true or false, we need to understand the definition of kinetic energy. Kinetic energy (KE) is defined as half of an object's mass (m) multiplied by its velocity squared (v^2). Since velocity is a measure of motion, it aligns with the statement that kinetic energy is the energy of motion. Therefore, the statement is TRUE.
3. Stopping distance is doubled if speed is doubled.
To determine if this statement is true or false, we need to analyze the relationship between stopping distance and speed. Stopping distance is influenced by various factors such as reaction time, braking efficiency, and road conditions. However, speed plays a crucial role. Assuming other factors remain constant, stopping distance will increase if speed is doubled. This increase may not be exactly double due to other factors, but the statement still holds true. Therefore, the statement is TRUE.
4. Work is the product of force and time.
To determine if this statement is true or false, we must understand the definition of work. Work (W) is defined as the product of force (F) and the displacement (d) in the direction of the applied force. Time is not a factor in the equation for work. Therefore, the statement is FALSE.
5. A joule is a newton times a second.
To determine if this statement is true or false, we need to understand the measurement units involved. A newton (N) is the unit of force, and a second (s) is the unit of time. A joule (J) is the unit of energy. Since work (energy) is the product of force and displacement (not time), the statement is FALSE.
6. Work is done to lift an object in the classroom.
To determine if this statement is true or false, we have to consider the definition of work again. Work is only done when a force is applied to an object, causing it to move in the direction of the force. If an object is lifted in the classroom, work is indeed done because a force is applied against the force of gravity, and the object moves upward. Therefore, the statement is TRUE.