A hanging weight of mass 9.0-kg is connected by an ideal str…

A hanging weight of mass 9.0-kg is connected by an ideal string going over a zero-mass pulley to a flat 5.0-kg block sliding on a flat table. If the coefficient of sliding (kinetic) friction is 0.19 and the contact surface is 0.36 m2, find the tension in the string (in Newtons).

A miniature, spring-loaded, radio-controlled gun is mounted…

A miniature, spring-loaded, radio-controlled gun is mounted on an air puck. The gun’s bullet has a mass of 6.00 g, and the gun and puck have a combined mass of 130 g. With the system initially at rest, the radio-controlled trigger releases the bullet, causing the puck and empty gun to move with a speed of 0.500 m/s. Of the total kinetic energy of the gun-puck-bullet system, what percentage is in the bullet?