Momentum
What is the basic equation for momentum(p) and Impulse(J)?
Answer: P = mv, J = ft
Repeated back and forth movement over the same path about an equilibrium position where the net force on the system is a restoring force.
Answer: Simple Harmonic Motion(SMH)
A positively charged particle has a magnetic field directed in the negative z direction and is moving in the positive x direction. What is the direction of the force from the magnetic field on the particle?
A) Negative X
B) Positive Y
C) Negative Y
D) Positive Z
Answer: B, Positive Y
A magnet is placed near the end of a coil of wire, with the North side facing away from the coil, and the South side facing towards the coil. If the magnet is moved towards the coil, which direction will the magnetic field created by the current be directed?
A) North
B) South
C) Towards the magnet
D) Away from the magnet
Answer: D, Away from the magnet
True or False, Momentum is a scalar quantity.
Answer: False, it is a vector quantity.
What equation relates to Hooke’s Law
Answer: F = -kx
If a magnetic field produces a force of 1.2*10^-5 Newtons, and a charged particle with an initial velocity of 12m/s has traveled a total of 20cm, how much work has been done by the magnetic field?
A) Zero
B) .24*10^-4
C) 2.4*10^-4
D) .24*10^-5
Answer: A, Zero
A wire with a radius of .2 cm produces a magnetic field of 5 T. If the magnetic field passes through a surface with a 45 degree angle. The strength of the magnetic field then triples. What is the change in the magnetic flux through the angled object?
A) 1.88E-5 W
B) 1.33E-4 W
C) 8.88E-5 W
D) 1.25E-4 W
Answer: C, 8.88E-5 W
Equations for Elastic and Inelastic Collisions. Pick Two.
A) m1v2 + m2v1 = (m1 + m2)vf
B) m1v1 + m2v2 = m1v1’ + m2v2’
C) F = ma
D) m1v2 + m2v1 = m1v2’ + m2v1’
E) m1v1 + m2v2 = (m1 + m2)vf
Answer: B) m1v1 + m2v2 = m1v1’ + m2v2’ and E) m1v1 + m2v2 = (m1 + m2)vf
What are the equations for Period(T) and B) Frequency of the oscillator(f)
A) T = 1/f and f = 2(pi)√mk
B) T = v/a and f = ma
C) T = 2(pi)√mk and f = 1/T
D) T = 45 and f = friends who do stuff together
Answer: C) T = 2(pi)√mk and f = 1/T
What is the correctly derived expression for the strength of a magnetic field from a current carrying wire from a distance d away from the wire, when d is greater than the radius of the wire?
A) UoI/(pi)d^2
B) UoNI/L
C) UoId/2(pi)R^2
D) UoI/2(pi)d
Answer: D, UoI/2(pi)d
Two coils of wire with of length L and magnetic fields of strength B are pushed towards a magnet. The first coil has N turns and travels a distance x in time t. If the second coil has twice as many turns and takes half the time as the first coil to travel the same distance, what is the induced voltage in the second coil?
A) Blx/t
B) NBlx/t
C) 4Blx/t
D) 4NBlx/t
Answer: D, 4NBlx/t
Fill in the blank. In an elastic Collision ____. In an inelastic Collision ____.
A) (both momentum and kinetic energy are conserved) (only momentum is conserved)
B) (only momentum is conserved) (both momentum and kinetic energy are conserved)
C) (only kinetic energy is conserved) (only momentum is conserved)
D)(only kinetic energy is conserved) (only momentum is conserved)
Answer: A) (both momentum and kinetic energy are conserved) (only momentum is conserved)
A force of 500N is used to stretch a spring with a 0.5kg mass attached to it by 0.35m. What is the value of the spring constant(k)
Answer: 1426.6 N/m
Two parallel current carrying wires have currents going in the same direction. There is a distance of .2 meters between them. If both wires have a current of 8 amps, what is the strength of the magnetic field at a point P, exactly halfway between the two wires?
A) 3.2*10^-5
B) 1.6*10^-7
C) 1.6*10^-5
D) Zero
Answer: A, 3.2*10^-5
A coil of wire with 25 turns and a diameter of 90 cm, is placed into a magnetic field of 2 T. If the magnetic field is reduced to zero T in .05 seconds, what is the induced Voltage inside the coil of wire?
A) 282.74 V
B) 14.14 V
C) 11.31 V
D) 942.48 V
Answer: A, 282.74 V
Free Response
A 500-gram cart rolls with negligible friction along a straight flat track until it collides with a 750-gram cart that was initially at rest. Position-time data for the 500-gram cart before it hits the other cart is recorded in the data table below. The collision takes place over a time period of 0.5 seconds.
x-position of 500-gram cart (cm)
0
10
20
30
40
time (s)
0
.5
1
1.5
2
A) At time t = 2 seconds, the two carts collide in a perfectly inelastic collision. Calculate the final velocity of the 500-gram cart after this collision.
B) Determine the impulse imparted to the 750g cart.
C) Determine the magnitude of the average force acting on the 500-g cart during the collision.
A: Impulse J = Ft 0.06N •s = F(0.5s) Favg = 0.12N
A) vf = 0.08m /s
B) J = 0.06kg•m/s or 0.06N•s
C) Favg = 0.12N
A Horizontal spring(K = 300 N/m) with a mass of 0.75kg attached to it is undergoing simple harmonic motion. Calculate the
A) period(T)
B) Frequency of the oscillator(f)
C) Angular Frequency/speed(ω)
Answer:
A) T = 0.3142 s
B) f = 3.183 Hz
C)ω = 20 rad/s
FRQ)
A solenoid with N turns, a varying length of L, a magnetic field of B, with an electric current provided by a series circuit varying voltage V with total resistance R.
A) Derive an expression for the number of turns on the coil of the solenoid.
B) What quantities would be graphed on the x and y axis to determine the number of turns in the coil of the solenoid?
A) Answer: N = BsLR/UoV
B) Answer: BsLR (at least L) on y-axis and UoV (at least V) on the x-axis
FRQ)
A magnet is placed to the left of a coil of wire, with the North side facing closest to the coil. The coil has N turns, a resistance of R and a diameter of d. The magnet is then pushed towards the coil of wire for a duration of t, producing an induced current of I.
A) What direction will the magnetic field produced by the electric current be facing? Explain.
B) Derive an expression for the strength of the magnetic field caused by the induced current in terms of d, I, N, R, t and other fundamental constants.
A) Answer: Directed towards the magnet, per Lenz's law the induced current will oppose the change in the magnetic field that causes it. Creates a North pole on the side of the coil closest to the magnet.
B) 4IRt/(pi)d^2