Three people pull simultaneously on a stubborn donkey. jack pulls directly ahead of the donkey with a force of 79.9 n , jill pulls with 73.3 n in a direction 45° to the left, and jane pulls in a direction 45° to the right with 137 n . (since the donkey is involved with such uncoordinated people, who can blame it for being stubborn? ) find the magnitude of the net force the people exert on the donkey.

Aball tossed vertically upward from the ground next to a building passes the bottom of a window 1.8 s after being tossed and passes the top of the window 0.20 s later. the window is 2.0 m high from top to bottom. what was the ball's initial velocity? the unit vector j^ is directed upward. how far is the bottom of the window from the launch position? how high does the ball rise above the launch position?

Awater-filled u-tube manometer is used to measure the pressure inside a tank that contains air. the water level in the u-tube on the side that connects to the tank is 5 ft above the base of the tank. the water level in the other side of the u-tube (which is open to the atmosphere) is 2 ft above the base. determine the pressure within the tank.

You've already seen the value of 9.8 in this lesson. what's this value called? what quantity does it represent?