Exam 7: Energy of a System

Two clowns are launched from the same spring-loaded circus cannon with the spring compressed the same distance each time. Clown A has a 40-kg mass; clown B a 60-kg mass. The relation between their kinetic energies at the instant of launch is

The graph below shows how the force on a 0.500 kg particle varies with position. If the particle has speed at x = 0.00 m, what is its speed in m/s when x = 8.00 m?

The force an ideal spring exerts on an object is given by F_x = −kx, where x measures the displacement of the object from its equilibrium (x = 0) position. If k = 60 N/m, how much work is done by this force as the object moves from x = −0.20 m to x = 0?

A 2.0-kg block situated on a frictionless incline is connected to a light spring (k = 100 N/m), as shown. The block is released from rest when the spring is unstretched. The pulley is frictionless and has negligible mass. What is the speed of the block when it has moved 0.20 m down the plane?

A constant force of 15 N in the negative y direction acts on a particle as it moves from the origin to the point m. How much work is done by the given force during this displacement?

Negative work can be done

A 1.5-kg object moving along the x axis has a velocity of +4.0 m/s at x = 0. If the only force acting on this object is shown in the figure, what is the kinetic energy of the object at x = +3.0 m?

The work done by the force exerted by the spring on a mass attached to the end of the spring when the mass has displacement d is

If vectors and have magnitudes 12 and 15, respectively, and the angle between the two when they are drawn starting from the same point is 110°, what is the scalar product of these two vectors?

The only force acting on a 2.0-kg body moving along the x axis is given by F_x = (2.0x) N, where x is in m. If the velocity of the object at x = 0 is +3.0 m/s, how fast is it moving at x = 2.0 m?

If the scalar (dot) product of two vectors is negative, it means that

After a skydiver reaches terminal velocity,

A body moving along the x axis is acted upon by a force F_x that varies with x as shown. How much work is done by this force as the object moves from x = 1 m to x = 8 m?

Two clowns are launched from the same spring-loaded circus cannon with the spring compressed the same distance each time. Clown A has a 40-kg mass; clown B a 60-kg mass. The relation between their speeds at the instant of launch is