The crate has a mass of 80 kg and is being towed by a chain which is always directed at 20...

The crate has a mass of 80 kg and is being towed by a chain which is always directed at 20° from the horizontal as shown. Determine the crate’s acceleration in t = 2 s if the coefficient of static friction is µ­s = 0.4, the coefficient of kinetic friction is µ­k = 0.3, and the towing force is P = (90t2) N, where t is in seconds.