a 60-kilogram high jumper lands on a mat after her jump. the mat brings her to a stop after 1 second. she
was traveling at 5.0 m/sec when she landed on the mat. note: the speed of the jumper at the top of her jump.
before she started to fall toward the mat, was 0 m/sec.
a. what is the change in momentum for the jumper?
b. what is the force felt by the jumper upon impact with the mat?

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)

You can watch static electricity in action by rubbing an inflated balloon against your hair. your hair will actually stand on its end! it does this because each hair becomes charged, and they all repel one another.

If a star is moving toward earth, it is