Energy Big Review

A 5 kg ball is lifted 12 m above the ground. The ball:

• gains elastic potential energy

• gains gravitational potential energy

• gains kinetic energy

• gains mechanical energy

A student is asked to determine the work done on a block of wood when the block is pulled horizontally using an attached string. The student is supplied with a spring scale, a stopwatch, and a meterstick. Which of the following graphical analysis techniques will allow the student to determine the work done on the block by the string?

• Graphing the force as a function of time and calculating the slope

• Graphing the force as a function of time and calculating the area under the curve

• Graphing the force as a function of distance and calculating the slope

• Graphing the force as a function of distance and calculating the area under the curve

An object is released from rest at a height H near and above the surface of Earth. As the object falls toward the surface, Earth’s atmosphere exerts a resistive force on the object such that it reaches a terminal velocity before it reaches the ground. Which of the following claims is true? Select two answers.

• The system consisting of only the object is an open system.

• Earth’s atmosphere does negative work on the object as it falls toward the surface.

• The change in the object’s kinetic energy from the instant it is released from rest, to the instant it reaches terminal velocity, is zero.

• The total mechanical energy of the object-Earth system remains constant at all times in which the object is in motion.

Tags

NGSS.HS-PS2-1

A rubber ball with mass 0.20 kg is dropped vertically from a height of 2 m above a floor. The ball bounces off of the floor, and during the bounce 0.50 J of energy is dissipated. What is the maximum height of the ball after the bounce?

• 3 m

• 2.15m

• 1.75 m

• 1.56 m

Tags

NGSS.HS-PS3-1

Which position has the most potential energy?

• A
• G
• C
• D

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-2

A small block of mass M=0.10 kg is released from rest at point 1 at a height H=1.8 m above the bottom of a track, as shown in the diagram. It slides down the track and around the inside of a loop of radius R=0.6 m. The speed of the block is 2.5 m/s at point 3. Which of the following claims about the situation is correct?

• The gravitational potential energy of the block-Earth system at point 3 is less than the gravitational potential energy at point 2.

• The kinetic energy of the block at point 3 is greater than the kinetic energy of the block at point 2.

• The mechanical energy of the block-Earth system at point 3 is less than the mechanical energy of the block-Earth system at point 1.

• The mechanical energy of the block-Earth system at point 2 is equal to the gravitational potential energy of the block-Earth system at point 1.

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-2

A block of mass M on an inclined surface is attached to a spring of negligible mass, as shown. The other end of the spring is attached to a wall, and there is negligible friction between the block and the incline. The block is pulled to a position such that the spring is stretched from its equilibrium position. The block is then released from rest. Which of the following systems can be classified as a closed system?

• A system consisting of the block only

• A system consisting of the spring and Earth

• A system consisting of the block and spring

• A system consisting of the block, spring, and Earth

Tags

NGSS.HS-PS3-1

A beat is dropped from the edge of a cliff. Which of the following graphs best represents the beat's kinetic energy KE as a function of time t?

• 
• 
• 
• 

Tags

NGSS.HS-PS2-1

NGSS.HS-PS3-1

NGSS.HS-PS3-2

A spring is compressed by a force F against a wall as shown. Which of the following describes the sign of work done by the spring as it is being compressed?

• The spring does positive work since it is gaining potential energy.

• The spring does zero work since all the work is done by force F.

• The spring does negative work since it applies a force against the direction of its compressing motion.

Tags

NGSS.HS-PS2-1

A 2 kg ball is attached to a 0.80 m string and whirled in a horizontal circle at a constant speed of 6 m/s. The work done on the ball during each revolution is:

• 90 J 

• 72 J

• 16 J

• zero

Answer explanation

In a circle moving at a constant speed, the work done is zero since the Force is always perpendicular to the distance moved as you move incrementally around the circle