Abatter hits a pop-up straight up over home plate at an initial velocity of 21 m/s. the ball is caught by the catcher at the same height that it was hit. at what velocity does the ball land in the catcher's mitt? neglect air resistance. (take the positive direction to be upwards.)

Three different objects, all with different masses, are initially at rest at the bottom of a set of steps. each step is of uniform height . the mass of each object is a multiple of the base mass : object 1 has mass 4..00m , object 2 has mass 1..96m , and object 3 has mass . when the objects are at the bottom of the steps, define the total gravitational potential energy of the three-object system to be zero. if the objects are then relocated as shown, what is the new total potential energy of the system? each answer requires the numerical coefficient to an algebraic expression. each algebraic expression is given using some combination of the variables , , and , where is the acceleration due to gravity. enter only the numerical coefficient. (example: if the answer is 1..23mgd , just enter 1.23)

1.what is where an object is located 2. what is how fast an objects speed is changing 3. what is how fast an object is moving

An alien spaceship is 500 m above the ground and moving at a constant velocity of 150 m/s upwards. how high above the ground is the ship after 5 seconds?