A man stands on a platform that is rotating (without friction) with an angular speed of 1.01 rev/s; his arms are outstretched and he holds a brick in each hand. The rotational inertia of the system consisting of the man, bricks, and platform about the central axis is 4.34 kg·m2. If by moving the bricks the man decreases the rotational inertia of the system to 1.68 kg·m2, (a) what is the resulting angular speed of the platform and (b) what is the ratio of the new kinetic energy of the system to the original kinetic energy?

Calculate the kinetic energy of earth due to its spinning about its axis. krot = j compare your answer with the kinetic energy of the orbital motion of earth's center of mass about the sun. assume earth to be a homogeneous sphere of mass 6.00 1024 kg and radius 6.40 106 m. the radius of earth's orbit is 1.50 1011 m.

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? question 2 options: the balloons rise at the same rate. both balloons are the same size. the ballons both rise. the cold ballon is larger than the warm balloon. the cold balloon expands and rises. the warm balloon shrinks and sinks. the warm balloon expands and rises. the cold balloon shrinks and sinks.

Steelhead trout migrate up stream to spawn.occasionally they need to leap up small waterfalls to continue their journey. fortunately, steelhead are remarkable jumpers, capable of leaving the water at a speed of 8.0 m/s. a. what is the maximum height a steelhead trout can jump? b.leaving the water at 8.0 m/s, the trout lands on top of the water fall 1.8 m high. how long was it in the air?