9. 2) The target is a thin 4.3-kg circular disk of radius r= 273 mm that can rotate freely about the z axis. Initially it is at rest. A 21-g bullet, traveling at v = 630 m/s, strikes the target at A and becomes embedded in it. The dimensions are di = 219 mm and d2 = 90 mm. If the impact time is 0.02 s, determine the average impact force between the bullet and the target. Please pay attention: the numbers may change since they are randomized. Your answer must include 2 places after the decimal point, and proper Sl unit. Take g = 9.81 m/s?. 'pe

The rigid object shown below consists of three balls and three connecting rods, with M = 1.6 kg, L = 0.6 m and 0 = 30°. The balls may be treated as particles, and the connecting rods have negligible mass. Determine the rotational kinetic energy of the object if it has an angular speed of w = 1.2 rad/s about (a) an axis that passes through_point P and is perpendicular to the plane of the figure, coming out towards your eyes and (b) an axis that passes through point P and lies on the rod of length 2L in the plane of the figure. (Hint: the distance from a particle to the axis of rotation is the_length of the line connecting the particle to the axis that is perpendicular to the axis.) 2M L 2L M L 2M

Solve B,C,D

1. Two children A and B, each having a mass 30kg, sit at the edge of the merry-go-round which is rotating with angular velocity @ = 2 rad/s. Excluding the children, the merry-go-round has a mass 180 kg and a radius of gyration k₂ = 0.8m. Determine the angular velocity of the merry-go-round if A jumps off horizontally in the -n direction (away from the merry-go-gound) with a speed of 3 m/s, measured with respect to the merry-go-round. After A jumps off, B then jumps off horizontally in the +t direction with a speed of 3 m/s, measured with respect to the merry-go-round - what is the merry-go-round's angular velocity now? Neglect friction and the size of each child. 1m 1m B w = 2 rad/s

The 10-kg bar is released from rest in the horizontal position 1 and falls to positions 2. The unstretched lengthy of the spring is 0.6 m and the spring constant is k=20 N/m .what will be the bar 's angular velocity when  it is in position 2.

The velocity of the 7.6-kg cylinder is 0.49 m/s at a certain instant. What is its speed v after dropping an additional 1.87 m? The mass of the grooved drum is m = 10.1 kg, its centroidal radius of gyration is k = 260 mm, and the radius of its groove is r; = 225 mm. The frictional moment at O is a constant 15.3 N-m. Assume r, = 345 mm. m Answer: v = i m/s

P

A cylinder of mass m = 25 kg, initially at rest when t = 0, is acted upon by the force F as shown. Assuming that the disk rolls without slipping, determine the velocity of the cylinder's center G after 16 %3D %3D seconds. Write your answer in m/s but do not write the units. R = 0.4 m F = 120 N Taylor e am Answer:

The uniform disk is initially at rest and has a mass of 24 kg. Its moment of inertia about its mass center is given by I =mr². A 100 N (constant) force F acts upon it as shown and it rolls without slip on the horizontal surface. Find: a) The velocity of its mass center G after it has moved 1.8 m. b) Include a detailed free body diagram(s)! f-100 N

The velocity of the 8.2-kg cylinder is 0.46 m/s at a certain instant. What is its speed v after dropping 1.28 m? The mass of the grooved drum is m 12.8 kg, its centroidal radius of gyration is k 305 mm, and the radius of its groove is r 255 mm. The frictional moment at Ois a constant 9.0 N-m. an additional V Assume ro 400 mm. т i Answer: v m/s