SAT Physics: Newton’s Laws Practice Test

1. Two point charges of charge +Q are placed as shown below. At what point will a negative charge experience a force toward the bottom of the page?

a) A
b) B
c) C
d) D
e) E
2. Four point charges are placed in the corners of a square, as shown in the figure below. If q_b = 10^-9C, q_c = -10^-9C and q_d = 10^-9C, and the magnitude of the electric forces on q_c is 0 N, which of the statements below is true?

a) q_c > 10^-9C
b) 0 < q_c < 10^-9C
c) q_c = 0C
d) -10^-9C < q_c < 0C
e) q_c < -10^-9C
3. The magnitude of the electric field generated by a charge q at a distance d1 from the charge is E1. What is the magnitude of the electric field generated by the charge at a distance d2 from the charge?
a) E1
b) E1·(d₂²/d₁²)
c) E1·(d₁²/d₂²)
d) E1·(d₁/d₂))
e) E1·(d₂/d₁))
4. What is the capacitance between the points A and B if C₁ = C₂ = C₃ = 10^-6F?

5. A DC voltage source is connected to two resistors in series, as shown in the figure below. What is the ratio between the power dissipation of resistor R₁ and the power dissipation of resistor R₂?

6. A copper wire of length l₁ = 6 m and cross-sectional area of A₁ = 4 mm² has the same resistance as another copper wire of length l₂ = 18m. What is the ratio between the masses of the two wires, m₂/m₁?
a) 9
b) 3
c) 1
d) 1/9
e) 1/3
7. A particle with a positive charge of q moves with a speed v and passes through a magnetic field B parallel with the speed v. What is the magnitude of the magnetic force on the particle?

a) F = qvB
b) F = -qvB
c) F = 0
d) F = qvB/2
e) F = -qvB/2
8. In the figure below, a magnetic field of .01 T is applied locally to a wire carrying a current of intensity I = 10A. What is the magnitude of the magnetic force applied to the wire?

a) F = .3N
b) F = .4N
c) F = .5N
d) F = 1N
e) F = 3N
9. Three parallel long straight wires carry currents as shown in the picture below. If the currents in the wires #1 and #2 are I = 5A, and the magnetic force on wire #1 is equal to 0A, what is the current in wire #3?

a) I₃ = 5A
b) I₃ = 10A
c) I₃ = 15A
d) I₃ = 20A
e) I₃ = 25A
10. Two metallic bars slide along metallic rails at speeds v₁ = .1m/s and v₂ = .2m/s as shown below. The bar and the rails are situated in a magnetic field of 4T. What is the induced voltage in the bar and rails?

a) 50mV
b) 60mV
c) 100mV
d) 120mV
e) 150mV

Solutions:
Question #1: b
Question #2: e
Question #3: c
Question #4: c
Question #5: d
Question #6: a
Question #7: c
Question #8: b
Question #9: d
Question #10: d