Acrate resting on a horizontal floor (\muμs = 0.61, \muμk = 0.3 ) has a horizontal force f = 49 newtons applied to the right. this applied force is the maximum possible force for which the crate does not begin to slide. if you applied this same force after the crate is already sliding, what would be the resulting acceleration (in meters/second2) ?

Scientists use laser range-finding to measure the distance to the moon with great accuracy. a brief laser pulse is fired at the moon, then the time interval is measured until the "echo" is seen by a telescope. a laser beam spreads out as it travels because it diffracts through a circular exit as it leaves the laser. in order for the reflected light to be bright enough to detect, the laser spot on the moon must be no more than 1.0 km in diameter. staying within this diameter is accomplished by using a special large-diameter laser. part a if λ = 540nm , what is the minimum diameter of the circular opening from which the laser beam emerges? the earth-moon distance is 384,000 km. express your answer to two significant figures and include the appropriate units.

Write a hypothesis about the effect of increasing resistance on the current in the circuit. use theformat and be sure to answer the lesson question. “how do changes in voltage or resistance affect current in an electric circuit? ”

In a game of pool, ball a is moving with a velocity v0 of magnitude v0 = 15 ft/s when it strikes balls b and c, which are at rest and aligned as shown. knowing that after the collision the three balls move in the directions indicated and assuming frictionless surfaces and perfectly elastic impact (that is, conservation of energy), determine the magnitudes of the velocities va, vb, and vc.