A block slides down a rough incline of 30° with coefficient of kinetic friction 0.2 (g = 10 m s⁻²). Its acceleration down the incline is:
A3.3 m s⁻²
B1.7 m s⁻²
C5.0 m s⁻²
D2.7 m s⁻²
Answer & Solution
Correct answer: A. 3.3 m s⁻²
Down the incline a = g(sinθ − μk cosθ) = 10(0.5 − 0.2×0.866) = 10(0.5 − 0.173) = 3.3 m s⁻². The value 5.0 wrongly ignores friction.
Related questions
A constant force of 6 N acts for 4 s on a 2 kg body initially at rest. The kinetic energy A stone of mass 0.5 kg is whirled in a horizontal circle of radius 1 m at constant angularA car of mass 1000 kg accelerates from rest to 20 m s⁻¹ in 5 s on a level road. The net hoA man weighing 50 kg jumps off a stationary boat of mass 250 kg into water with a horizontNewton's third law states that 'action and reaction are equal and opposite'. The most accuTwo identical billiard balls strike a smooth rigid wall with equal speeds u. Ball A strikeA force F acts on a particle making an angle θ with its instantaneous velocity. The componA cricketer draws his hands back while catching a fast ball. The physical reason is that: