A stage crew member uses a pulley system to close the curtains on stage. If he does 620 Joules of work and the pulley system does 415 Joules of work, the efficiency of the pulley system is

d) the number of neutrons plus the number of protons

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask

here we know that ball will drop down by total distance 3.2 m

so here we know that

now using kinematics

now in the same time it will cover horizontal distance of 0.75 m

so speed of the ball will be