1) A 0.40-kg mass attached to a spring is pulled back horizontally across a table so that the potential energy of the system is increased from zero to 155 J. Ignoring friction, what is the kinetic energy of the system after the mass is released and has moved to a point where the potential energy has decreased to 70 J?

The kinetic energy of the system after the mass is released and has moved to a point where the potential energy has decreased to 70J is J.

2) A horizontally directed force of 30-N is used to pull a box through a distance of 2.4 m across a tabletop. How much work is done by the 30-N force?

The work done by the 30-N force is J.

3) A ball traveling in a circle with a constant speed of 15 m/s has a centripetal acceleration of 20 m/s². What is the radius of the circle?

The radius of the circle is m.

4) A wheel with a rotational inertia of 8.3 kgm² accelerates at a rate of 3.4 rad/s². What net torque is needed to produce this acceleration?

The net torque required to produce the acceleration is Nm.

5) A student, sitting on a stool, holds masses in each hand. When his arms are extended, the total rotational inertia of the system is 5.6 kgm². When he pulls his arms in close to his body, he reduces the total rotational inertia to 1.4 kgm². When he is rotating with his hands held close to his body, his rotational velocity is 18 RPM. If there are no external torques, calculate the new rotational velocity of the system when he extends his arms.

The new rotational velocity of the system is RPM.

6) A roller-coaster car has a potential energy of 900 kJ and a kinetic energy of 180 kJ at point A in its travel. At the low point of the ride, the potential energy is zero, and 60 kJ of heat has been generated by friction since it left point A. What is the kinetic energy of the roller coaster at this low point?

The kinetic energy of the roller coaster at its low point is kJ.

7) A rocket ship at rest in space gives a short blast of its engine, firing 59 kg of exhaust gas out the back end with an average velocity of 450 m/s. What is the magnitude of the change in momentum of the rocket during this blast?

The magnitude of the change in momentum of the rocket is 10⁴ kgm/s.

8) The rotational velocity of a merry-go-round increases at a constant rate from 0.9 rad/s to 6.6 rad/s in a time of 8.5 s. What is the rotational acceleration of the merry-go-round?

The rotational acceleration of the merry-go-round is rad/s².

9) Dylan has a weight of 500 N when he is standing on the surface of the Earth. What would his weight (the gravitational force due to the Earth) be if he tripled his distance from the center of the Earth by flying in a spacecraft?

His weight would be N when the distance from the center of the Earth is tripled.

10) The frequency of oscillation of a pendulum is 24 cycles/s. What is the period of oscillation?

The period of oscillation of the pendulumis s.

11) A weight of 85 N is located at a distance of 8 cm from the fulcrum of a simple balance beam. At what distance from the fulcrum should a weight of 25 N be placed on the opposite side in order to balance the system?

The required distance from the fulcrum to balance the system is cm.

12) The time required for one complete cycle of a mass oscillating at the end of a spring is 0.7 s. What is the frequency of oscillation?

The frequency ofoscillation is Hz.