18. If one ball with a momentum of 50 kg. m/s hits a ball at rest and no other forces are acting on either ball, what's
the total momentum of both balls after the collision?
O A. O kg. m/s
O B. 50 kg. m/s
O C. 25 kg. m/s
O D. 100 kg. m/s

Ascientist is tracking an object orbiting the sun that is found between mars and jupiter. in order to classify the object as an asteroid, it must be at least

Why don't you see your reflection in water with waves or repples

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.