A toy cannon uses a spring to project a 5.23-g soft rubber ball. The spring is originally compressed by 5.05 cm and has a force constant of 7.92 N/m. When the cannon is fired, the ball moves 14.2 cm through the horizontal barrel of the cannon, and the barrel exerts a constant friction force of 0.032 1 N on the ball. With what speed does the projectile leave the barrel of the cannon?
a. 2.68 m/s
b. 1.58 m/s
c. 2.40 m/s
d. 1.38 m/s

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.

6–48 bananas are to be cooled from 24 to 138c at a rate of 215 kg/h by a refrigeration system. the power input to the refrigerator is 1.4 kw. determine the rate of cooling, in kj/ min, and the cop of the refrigerator. the specific heat of banana above freezing is 3.35 kj/kg·8c.

How are positive ions different from neutral atoms