A 4.0-kg mass is placed at (3.0, 4.0) m, and a 7.0-kg mass is placed at (3.0, -4.0) m. What is the moment of inertia of this system of masses about the x axis?

Bumpers on cars are not of much use in a collision. To see why, calculate the average force a bumper would have to exert if it brought a 1200-kg car

(a so-called compact model) to a rest in 15 cm when the car had an initial speed of 2.0 m/s (about 4.5 mph). (Bumpers are built with springs that compress to provide a stopping force without, hopefully, denting the metal.) A) 1.8 × 104 N B) 1.6 × 104 N C) 5.4 × 104 N D) 6.5 × 105 N E) 3.2 × 104 N

Between 0°C and 4°C, the volume coefficient of expansion for water:

a. is positive. c. is becoming less dense. b. is zero. d. is negative.

Fish don't live very long in water that has just been boiled and brought back to room temperature. Suggest why

A) There is now a higher concentration of dissolved CImage in the water. B) The nutrients in the water have been destroyed. C) Since some of the water was evaporated while boiling, the salts in the water are now more concentrated. This has a negative effect on the fish. D) The boiling process removes the air that was dissolved in the water. Upon cooling the water is void of its usual air content, hence, the fish drown.

A miniature, spring-loaded, radio-controlled gun is mounted on an air puck. The gun's bullet has a mass of 5.00 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? a. 50% c. 3.4% b. 96% d. 100%