A block of mass 10 kg is on a horizontal table with

Solution

• Mass of block on table: M = 10 kg
• Coefficient of friction: μ = 0.2
• Suspended mass: m = 4 kg
• Gravitational acceleration: g = 10 m/s²
• Pulley is frictionless, and the string is light and inextensible

• The 10 kg block is on the table and connected to the 4 kg hanging mass via a pulley.
• Let the entire system move with acceleration a.
• Let the tension in the string be T.

• Downward force: m·g = 4 × 10 = 40 N
• Upward tension: T
• Equation of motion:
  m·g – T = m·a
  ⇒ 40 – T = 4a → (1)

• Horizontal tension pulling right: T
• Friction opposes motion: f = μ·M·g = 0.2 × 10 × 10 = 20 N
• Net force: T – f = M·a
  ⇒ T – 20 = 10a → (2)