AP Energy

A baguette is dropped off the top of the Eiffel Tower. What is true concerning of the mechanical energy of the ball as it falls?

• The potential energy of the baguette is conserved as it falls.

• The sum of the kinetic and potential energies of the baguette is a constant.

• The kinetic energy of the baguette is conserved as it falls.

• A) The total energy of the object increases as it falls since it gains speed.

Tags

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.

• The spring works part-time at Chik Fil-A.

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-2

A roller coaster car of mass m has a speed of 0 m/s just before it starts to go down a hill as show above. Assume the roller coaster does not encounter any friction or air resistance. What is the speed of the roller coast car at point B?

• $\sqrt{gh}$

• $\sqrt{2gh}$

• $\sqrt{\frac{gh}{2}}$

• $\sqrt{\frac{2gh}{m}}$

Tags

NGSS.HS-PS3-2

In which of the following situations is kinetic energy decreasing?

• A lit tinsel llama is dropped from a building.

• A satellite is moving in a circular orbit around the moon.

• A baseball is headed upward after being thrown up in the air.

• An elevator is moving upward at a constant velocity.

Tags

NGSS.HS-PS3-2

A dude drags a car mass M across a rough floor with a force of magnitude directed at an angle theta of above the horizontal as shown. If he drags the crate for a distance D, which of the following is equal to the work by the force of friction?

• $-F\cos\theta D$

• $-\mu mgD$

• $-\mu\left(mg-F\sin\theta\right)D$

• $-\mu\left(mg+F\cos\theta\right)D$

Tags

NGSS.HS-PS2-1

Bill and Ted both push a crate of mass m crate across a floor with friction at constant speed. Bill pushes the crate d meters in 100 seconds. Ted takes 200 seconds to push the crate the same distance. Which of the following is true?

• More power is developed when Ted pushes the crate.

• More power is developed when Bill pushes the crate.

• An equal, non-zero amount of power is developed in both cases.

• Power is not developed in either case since the crate travels at constant velocity in both cases

A car of mass m is traveling at a speed of when the driver applies the brakes. The car moves a distance of d before it stops completely. What is the magnitude of the braking force required?

• $\frac{2d}{v^2}$

• $\frac{mv^2}{2d}$

• $\frac{2v^2}{d}$

• $\frac{mv}{d}$

Tags

NGSS.HS-PS2-1

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-PS3-2

A penguin of mass M is lifted upwards a vertical distance of H at a constant speed of v. Which of the following gives a correct expression for the power developed by the penguin as it is raised upward at constant speed?

• $Mgv$

• $\frac{mg}{v}$

• $\frac{mgh}{v}$

• $mgh$

Tags

NGSS.HS-PS3-1

The system shown consists of two objects of unequal masses, M₁ and M₂, and pulley with negligible mass and friction. Which of the following is true about the changes in the gravitational potential energy and kinetic energy of the system soon after the objects are released from rest?

• $\Delta U\ =\ 0\ and\ \Delta K>0$

• $\Delta U>0\ and\ \Delta K>0$

• $\Delta U<0\ and\ \Delta K>0$

• $\Delta U=0\ and\ \Delta K=0$

Tags

NGSS.HS-PS3-1