A 75 kg barrel is pulled up by a rope. The barrel accelerates at 3".4 m"/s^2. Find the force exerted on the barrel by the rope. Show all your work. please help I don't understand physics

Taylor's experiment: 1. accurately measured the speed of light 2. locked together the phases of two light sources so that the interference pattern would not shift 3. showed that man's reaction time was much slower than the speed of light 4. showed that individual photons have wave characteristics

You are given a vector a = 125i and an unknown vector b that is perpendicular to a. the cross-product of these two vectors is a × b = 98k. what is the y-component of vector b?

Should we celebrate the voyages of zheng he mini q answer key