The magnitude of the force required to compress an imperfect horizontal spring a distance x is given by f=kx+bx3 where k = 120 n/m and b = 18 n/m3. if you use a 3.5-kg block to compress the spring a distance of 2.2 m and then let it go, what speed will the block have when it leaves the spring? assume the surfaces are smooth enough that any frictional forces can be neglected.

Two particles of masses m and 2m are placed on a smooth horizontal table. a string, which joins these two masses, hangs over the edge supporting a pulley, which suspends a particle of mass 3m. the pulley has negligible mass. the two parts of the string on the table are parallel and perpendicular to the edge of the table. the hanging parts of the string are vertical. find the acceleration of the particle of mass 3m.

Aphysical change is a change in the size, shape,, or stafe of matter true or false

Very large accelerations can injure the body, especially if they last for a considerable length of time. one model used to gauge the likelihood of injury is the severity index ( ), defined as =/ . in the expression, is the duration of the accleration, but is not equal to the acceleration. rather, is a dimensionless constant that = the number of multiples of that the acceleration is equal to. in one set of studies of rear-end collisions, a person's velocity increases by 13.7 km/h with an acceleration of 36.0 m/s2 . let the + direction point in the direction the car is traveling. what is the severity index for the collision?