A boy throws a ball at a wall. The ball hits the wall with a force of 250 N. How large of a force does the wall exert on the wall?

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)

What is the primary force that suspension bridges use cables to hold their spans up? a. tension force b. resistance force c. normal force d. elastic force e. applied force

What is the temperature in degrees celsius of a substance with a tempature of 49k