An object falls freely in a straight line and experiences air resistance proportional to its speed; this means its acceleration is a(t)equals minuskv(t), where k is a positive constant and v is the object's velocity. the speed of the object decreases from 1100 ft divided by s to 1000 ft divided by s over a distance of 1300 ft . approximate the time required for this deceleration to occur. hint: note that a(t)equals v prime (t ) and v(t)equals x prime (t ).
the time required for this deceleration to occur is approximately seconds. (do not round until the final answer. then round to four decimal places as needed.)

Anne applies a force on a toy car and makes it move forward. what can be said about the forces acting on the toy car at the moment anne applies the force?

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)

Iwill give 30 points to whoever answers ! what is the formula for actual mechanical advantage and ideal mechanical advantage?