Advertising in the Telegram channel «𝚔𝚗𝚘𝚠𝚕𝚎𝚍𝚐e 🄷🅄🄱» from 3.60

Channel info
Full statistics

Recent Channel Posts

Natural or Social ናቹ?

17:11

02.03.2026

Physics Grade 12 Unit 2 Two-dimensional motion
MCQs with Answers and explanations

Q1. A projectile is launched at an angle θ above the horizontal with initial speed v₀. At the highest point of its trajectory, which statement is true?
A) Its velocity is zero.
B) Its acceleration is zero.
C) Its vertical velocity is zero, but horizontal velocity remains constant.
D) Its kinetic energy is maximum.

Answer: C
Explanation: At the peak, vertical velocity becomes zero due to gravity, but horizontal velocity remains unchanged (assuming no air resistance). Acceleration is always g downward.

Q2. Two projectiles are launched with the same speed: one at 30° and the other at 60° to the horizontal. Which statement is correct (ignoring air resistance)?
A) The 30° projectile has a greater range.
B) The 60° projectile stays in the air longer.
C) Both have the same time of flight.
D) The 30° projectile reaches a higher maximum height.

Answer: B
Explanation: Complementary angles (θ and 90°−θ) give the same range, but the larger angle (60°) results in a greater vertical component → longer time of flight and higher max height.

Q3. A rigid body rotates about a fixed axis with constant angular acceleration. Which quantity remains constant?
A) Angular velocity
B) Tangential acceleration
C) Angular acceleration
D) Centripetal acceleration

Answer: C
Explanation: By definition, constant angular acceleration means α is constant. Angular velocity changes, and centripetal/tangential accelerations depend on ω or α and may vary.

Q4. An astronaut in a circular orbit around Earth feels “weightless” because:
A) There is no gravity in space
B) The gravitational force is balanced by a centrifugal force
C) Both the astronaut and spacecraft are in free fall toward Earth
D) The spacecraft’s engines cancel gravity

Answer: C
Explanation: Weightlessness occurs because both astronaut and spacecraft accelerate toward Earth at the same rate due to gravity—there’s no normal force acting, creating the sensation of zero weight

Q5. A solid sphere and a hollow sphere of the same mass and radius roll down an incline without slipping. Which reaches the bottom first?
A) Hollow sphere
B) Solid sphere
C) Both reach at the same time
D) Depends on the angle of incline

Answer: B
Explanation: The solid sphere has a smaller moment of inertia (I = 2/5 MR²) than the hollow sphere (I ≈ 2/3 MR²), so more of its gravitational potential energy converts to translational kinetic energy → faster acceleration.

Q6. Torque (τ) acting on a rotating object is related to angular acceleration (α) by:
A) τ = Iα
B) τ = ma
C) τ = Fr
D) τ = L/t

Answer: A
Explanation: This is Newton’s second law for rotation: net torque equals moment of inertia times angular acceleration.

Q7. According to Kepler’s second law, a planet moves fastest when it is:
A) Farthest from the Sun (aphelion)
B) Closest to the Sun (perihelion)
C) At the midpoint of its orbit
D) Moving perpendicular to the Sun-planet line

Answer: B
Explanation: Kepler’s second law (law of equal areas) implies that orbital speed increases as the planet gets closer to the Sun to sweep equal areas in equal times.

Q8. Kepler’s third law states that the square of the orbital period (T) of a planet is proportional to:
A) The cube of its average distance from the Sun (r³)
B) The square of its average distance (r²)
C) Its mass
D) The inverse of its orbital speed

Answer: A
Explanation: T² ∝ r³ — this applies to all planets orbiting the same central body (e.g., the Sun).

Q9. If the distance between two masses is tripled, the gravitational force between them becomes:
A) One-third
B) One-ninth
C) Three times
D) Nine times

Answer: B
Explanation: F ∝ 1/r². If r→ 3r, then F → F/9.

JOIN SHARE REACT
KNOWLEDGE HUB

134