Physics: Classical Mechanics & Kinematics Flashcards

A satellite orbits Earth at constant speed in a circular orbit. Which statement correctly describes its motion?

Answer: Gravity provides centripetal force toward Earth's center

Gravity acts as centripetal force pulling the satellite toward Earth's center, causing circular orbital motion.

On an Atwood machine, masses of 3 kg and 5 kg are connected by a massless string over a frictionless pulley. What is the system's acceleration? (g = 10 m/s²)

Answer: 2.5 m/s²

For an Atwood machine, a = (m₂−m₁)g/(m₁+m₂) = (5−3)(10)/(3+5) = 20/8 = 2.5 m/s².

A position-time graph shows a straight line with a negative slope passing through the origin. What does this indicate?

Answer: The object moves at constant velocity in the negative direction

A straight line on a position-time graph means constant velocity; a negative slope means the object moves in the negative direction.

A 2 kg object is dropped from rest and falls for 3 s. Neglecting air resistance, what is its speed just before impact? (g = 10 m/s²)

Answer: 30 m/s

Using v = v₀ + at = 0 + 10(3) = 30 m/s.

An object travels in a straight line with increasing speed in the positive direction. Which combination correctly describes its velocity and acceleration?

Answer: v > 0, a > 0

Increasing speed in the positive direction means both velocity and acceleration are positive.

Two forces of 6 N and 8 N act perpendicular to each other on an object. What is the magnitude of the resultant force?

Answer: 10 N

For perpendicular forces, F_net = √(6² + 8²) = √(36 + 64) = √100 = 10 N.

A velocity-time graph shows a horizontal line at v = 5 m/s. Which is true?

Answer: The object moves at constant velocity with zero acceleration

A horizontal line on a velocity-time graph means constant velocity; slope (acceleration) is zero.