A rock of mass 51.2 kg accidentally breaks loose from the edge of a cliff and falls straight down. The magnitude of the air resistance that opposes its downward motion is 15.7 N. What is the magnitude of the acceleration of the rock?

Most aircraft need an airspeed of about 120 knots (61.7 m/s) to lift off. If a fully laden b-52 starts from rest with an acceleration of 4.16 m/s2, how long a runway does it need to be able to take off?

In a local diner, a customer slides an empty coffee cup down the counter for a refill. The cup slides off the counter and strikes the floor at distance d from the base of the counter. (a) If the height of the counter is h, find an expression for the time t it takes the cup to fall to the floor in terms of the variables h and g. t =        (b) With what speed does the mug leave the counter? Answer in terms of the variables d, g, and h. v1 =        (c) In the same terms, what is the speed of the cup immediately before it hits the floor? v2 =        (d) In terms of h and d, what is the direction of the cup's velocity immediately before it hits the floor? ? =         radians

A bullet shot straight up returns to its starting point in 59.1 s. embedding itself 16.9 cm deep in a wooden block. What is the average acceleration the bullet encounters in the block (in standard units)? Answer: Check