Regents Physics 2 — Questions and Answers
Question 1: A car traveling at 20 m/s applies its brakes and comes to rest in 4 seconds. What is the magnitude of the car's acceleration?
- 2.5 m/s²
- 5 m/s² (Correct answer)
- 10 m/s²
- 80 m/s²
Correct answer: 5 m/s²
Acceleration = Δv/Δt = (0 − 20)/4 = −5 m/s², so the magnitude is 5 m/s².
Question 2: Which of the following best describes a scalar quantity?
- Velocity
- Displacement
- Speed (Correct answer)
- Force
Correct answer: Speed
Speed has magnitude only (no direction), making it a scalar, while velocity, displacement, and force are vectors.
Question 3: A 5 kg object is acted upon by a net force of 15 N. What is its acceleration?
- 0.33 m/s²
- 3 m/s² (Correct answer)
- 75 m/s²
- 10 m/s²
Correct answer: 3 m/s²
Newton's second law: a = F/m = 15/5 = 3 m/s².
Question 4: An object is thrown horizontally from a cliff. Which component of its velocity increases as it falls?
- Horizontal
- Both horizontal and vertical
- Neither
- Vertical (Correct answer)
Correct answer: Vertical
Gravity accelerates the object downward, increasing the vertical component; horizontal velocity remains constant (ignoring air resistance).
Question 5: Two objects with charges +2 μC and −2 μC are placed 0.1 m apart. Compared to the force on the positive charge, the force on the negative charge is:
- Greater in magnitude
- Less in magnitude
- Equal in magnitude but opposite in direction (Correct answer)
- Equal in both magnitude and direction
Correct answer: Equal in magnitude but opposite in direction
Newton's third law applies to electrostatic forces: the forces are equal in magnitude but opposite in direction.
Question 6: What happens to the wavelength of a wave if its frequency doubles while the wave speed stays constant?
- It doubles
- It halves (Correct answer)
- It stays the same
- It quadruples
Correct answer: It halves
Since v = fλ and v is constant, if f doubles then λ must halve to keep the product constant.
Question 7: A 10 kg block rests on a frictionless horizontal surface. A horizontal force of 40 N is applied. What is the block's acceleration?
- 0.25 m/s²
- 4 m/s² (Correct answer)
- 400 m/s²
- 0.4 m/s²
Correct answer: 4 m/s²
a = F/m = 40/10 = 4 m/s².
Regents Physics 2
A car traveling at 20 m/s applies its brakes and comes to rest in 4 seconds.
What is the magnitude of the car's acceleration?