Question

A block of mass 1 kg is at rest on a horizontal table. The coefficient of static friction between the block and the table is 0.5. If g = 10 m s^–2 , then the magnitude of the force acting upwards at an angle of 60º from the horizontal that will just start the block moving is –

• A. 5 N
• B. 5.36 N
• C. 74.6 N
• D. 10 N

Answer 1

Answer: (B)

5.36 N

Answer 2

F cos 60⁰ = f ...(i)

f = µN = µ (1 g – F sin 60⁰) ...(ii)