line path displacement of 60 m. What is the vehicle's acceleration if its value may be assumed to be constant? b. 7.5 m/s 2 By how much is the energy stored in a Hooke's law spring increased when its stretch is increased from 8.00 cm to 15.00 cm? d. 252% Neglecting gravity, doubling the exhaust velocity from a single stage rocket initially at rest changes the final velocity attainable by what factor? Assume all other variables, such as the mass of the rocket and the mass of the fuel, do not change. d. The final velocity doubles. A baseball outfielder throws a baseball of mass 0.10 kg at a speed of 30 m/s and initial angle of 30 ° . What is the kinetic energy of the baseball at the highest point of the trajectory? Ignore air friction. a. 68 J A baseball catcher puts on an exhibition by catching a 0.150-kg ball dropped from a helicopter at a height of 100 m above the catcher. If the catcher "gives" with the ball for a distance of 0.500 m while catching it, what average force is exerted on the mitt by the ball? ( g = 9.80 m/s 2 ) d. 295 N A ceiling fan is turned on and reaches an angular speed of 120 rev/min in 20 s. It is then turned off and coasts to a stop in an additional 40 s. The ratio of the average angular acceleration for the first 20 s to that for the last 40 s is which of the following? . − 2 Rupel pushes a box 4.00 m by applying a 25.0-N horizontal force. What work does she do? a. 100 J Three different mass projectiles are launched from the top of a building each at different angles of elevation. Each particle has the same initial kinetic energy. Which particle has the greatest speed just as it impacts with the ground? d. They all will have the same speed on impact. A point on the rim of a 0.30-m radius rotating wheel has a tangential speed of 4.0 m/s. What is the tangential speed of a point 0.10 m from the center of the same wheel?