What is the acceleration of a train that takes 22 seconds to go from a speed of 73 kilometers per hour to a speed of 45 kilometers per hour?
A: 0.79 km/h/s
B: O -1.3 km/h?
C: 0 -1.1 km/h/s
D: 0 1.6 km/h s
E: 0-1.3 km/h/s

Which changes of state do the labels represent? a: b: c:

Hey student studies gravity using objects that have the same mass which two objects have the greatest gravitational force acting between them a. 100kg 1.0m 100kg b. 100kg 2.0m 100kg c. 100kg 2.0m 100kg big d. 100kg big 3.0m 100kg big

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.