Two equal-mass blocks A and B are released simultaneously on the same rough 45° incline. Their coefficients of kinetic friction are 0.2 and 0.3, and A starts √2 m behind B. Find the time in seconds for A to catch B. Take g = 10 m s⁻².

Question

G1 Physics · Accepted Answer

For block A, aₐ = g(sin45° - 0.2cos45°) = 4√2 m s⁻². For block B, aᵦ = g(sin45° - 0.3cos45°) = 3.5√2 m s⁻². Relative acceleration is 0.5√2 m s⁻². With initial gap √2 m and zero relative speed, √2 = ½(0.5√2)t², giving t = 2 s.