Ahuman cannonball leaves the cannon with a speed 15 m/s the performer's mass is 80 kg. the cannon barrel is 9 m long. find the average net force

A90db sound wave strikes an eardrum whose area is 5.0×10^-5m^2. how much energy is absorbed by the eardrum per second

How long will a plane have to fly continuously with 1100 miles per hour in order to cover the same distance as that from earth to the next star, proxima centauri?

1) a child holds two dogs on two separate leads. the dogs are pulling in different directions. one is pulling a force of 20n north and one is pulling 15n eastwards. calculate the resultant force on the child. state the direction. (use the parallelogram of forces) 2) a force of 20n acts horizontally on an object. a second force of 5n acts at 60 degrees to the first one. calculate the resultant force. worth 20 points, need answers asap with method you x