Benchmark Assessment Review 2

A common example of an object moving under the influence of a net unbalanced force is a falling object. If we ignore air resistance, the only force acting on the object is the gravitational force. A student uses video analysis to measure the position of a ball that is dropped from an initial height of 5.0 m from the ground. For this experiment, up is the positive y-direction and down is the negative y-direction. The student records the position of the ball every 0.25 seconds. Their data is given in the table. The student analyzes the data and realizes that the ball travels a greater distance in the time interval t = 0.75 s-1.0 s than it does in the time interval t = 0.0 s - 0.25 s. How can they use Newton's second law to explain this result?

• The gravitational force produces a constant acceleration on the ball which causes its speed to constantly decrease as it falls.
• The gravitational force produces an increasing acceleration on the ball which causes its speed to decrease as it falls.
• The gravitational force produces a decreasing acceleration on the ball which causes its speed to increase as it falls.
• The gravitational force produces a constant acceleration on the ball which causes its speed to constantly increase as it falls.

Caroline uses 20 N of force to move a box of books 15 m. How much work did she do?

• 0.75 J
• 300 J
• 1.33 J
• 35 J

Which electromagnetic wave has the highest frequency?

• Ultraviolet rays
• Gamma rays
• Visible light
• Radio waves

Which of the listed electromagnetic waves has the highest frequency?

• ultraviolet
• visible
• infrared
• microwave

A house needs to be moved 80.3 m horizontally to a different lot of land. If 39,000 J of work are required, how much force is needed?

• 486 N
• 49 N
• 48 N
• 488 N

Which of the following converts chemical energy ⇒ kinetic energy ⇒ electrical energy?

• a blender
• a generator
• an electric motor
• a wood stove

The frequency of a wave is observed twice overtime. The frequency of this wave is —

• increasing
• fluctuating
• staying the same
• decreasing

Internal forces do not have an impact on the total momentum of a system. If there is no net external force on a system, the total momentum of the system is conserved. Suppose a student invents a device that can be used during parades to launch small pieces of candy. Suppose the mass of the candy launcher is 100 times the mass of a single piece of candy. Which statement is true?

• The momentum of the candy launcher will be 100 times the momentum of the piece of candy immediately after it is launched.
• The speed of the piece of candy will be 100 times greater than the speed of the candy launcher immediately after it is launched.
• The speed of the candy launcher will be zero after the piece of candy is launched.
• The speed of the candy launcher and the piece of candy will be equal in magnitude but opposite in direction.

Internal forces do not have an impact on the total momentum of a system. If there is no net external force on a system, the total momentum of the system is conserved. Suppose a student invents a device that can be used during parades to launch small pieces of candy. Suppose the mass of the candy launcher is 100 times the mass of a single piece of candy. Which statement is true?

• The momentum of the candy launcher will be 100 times the momentum of the piece of candy immediately after it is launched.
• The speed of the piece of candy will be 100 times greater than the speed of the candy launcher immediately after it is launched.
• The speed of the candy launcher will be zero after the piece of candy is launched.
• The speed of the candy launcher and the piece of candy will be equal in magnitude but opposite in direction.

If it were possible for the input work on a lever to equal its output work, this simple machine would have an efficiency of which of the following choices?

• 0 %
• 50%
• 100%
• 150%