AP Physics Misconceptions

An open cart on a level surface is rolling without frictional loss through a verticle downpour of rain, as shown in the figure. As the cart rolls, an appreciable amount of the rainwater accumulates in the cart. The speed of the cart will

• increase because of conservation of mechanical energy

• decrease because of conservation of momentum

• decrease because of conservation of mechanical energy

• remain the same because the raindrops are falling perpendicular to the direction of the cart's motion

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-2

When there is a steady current in the circuit, the amount of charge passing a point per unit of time is

• Greater in the 2 Ω resistor than the 3  Ω resistor
• greater at point X than at Y
• greater in the 1 Ω resistor than the 2 Ω resistor
• Greater in the 1 Ω resistor than the 3  Ω resistor

A block of mass 3.0 Kg is suspended from a string, causing it to stretch 12cm before reaching equilibrium, as shown in the image.
The 3.0 Kg block is replaced with a 4.0 Kg block and it is released from the position shown above, at which the spring is unstretched.
How far will the 4.0 Kg block fall before the direction is reversed?

• 9 cm
• 18 cm
• 24 cm
• 32 cm

Tags

NGSS.HS-PS2-1

Two parallel conducting plates are connected to a constant voltage source.  The magnitude of the electric field between the plates is 2000 N/C.  If the voltage is doubled and the distance between the plates is reduced to 1/5 the original distance what is the strength of the new magnetic field

• 1,600 N/C
• 2,400 N/C
• 5,000 N/C
• 20,000 N/C

Two objects of mass 0.2 Kg and 0.1 Kg, respectively, move in the same direction. The 0.2 Kg object overtakes and collides with the 0.1 Kg object. Immediately after the collision the 0.2 Kg object is travelling 1 m/s upward.

What is the y-component of the 0.1 Kg mass immediately after the collision?

• 2 m/s Downward

• 1 m/s Downward

• 1 m/s Upward

• 2 m/s Upward

Tags

NGSS.HS-PS2-2

A ball of mass 0.4 Kg is initially at rest on the ground.  It is kicked and leaves the kicker's foot at a 60 degree angle above the horizontal at 5 m/s.  The magnitude of the impulse imparted by the foot to the ball is

• 1  1 N * s 
• 2  2 N * s 
• 3  3 N * s
• 4  4 N * s 

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-2

A rock of mass m is thrown horizontally off the top of a cliff of height h, as shown in the diagram.  The speed of the rock as it leaves the throwers hand is v.
How much time does it take for the rock to hit the ground?

• √hv
• h/√gv
• √(h/mg)
• √(2h/g)

What is the kinetic energy of the rock just before it hits the ground?

• mgh
• 1/2mv²
• 1/2mv² - mgh
• 1/2mv² + mgh

Tags

NGSS.HS-PS3-1

Two parallel conducting plates, separated by a distance, d, are connected to a battery of emf V.  
Which of the following is correct if the plate separation is doubled while the battery remains constant?

• The electric charge on the plates is doubled 
• The electric charge on the plates is halved 
• The potential difference between the plates is doubled 
• The potential difference between the plates is halved

An stationary object explodes, into 3 pieces of masses m, m and 3m.  Two pieces fly off at right angles to each another with the same momentum mV, as shown in the diagram. What is the magnitude and direction of the piece of mass 3m?

• V/√3    ↗
• (V√2)/3   ↙
• V/√3    ↙
• (V√2)/3  ↗ 

Tags

NGSS.HS-PS2-2