Phy11 Finals Reviewer.docx

1. Hockey puck B rests on a smooth ice surface and is struck by a second puck A, which has the same mass. Puck A is initially traveling at 15.0 m/s and is deflected 25 degrees from its initial direction. Assume that the collision is perfectly elastic. Find the final speed of each puck and the direction of B’s velocity after the collision.

2. Spheres A (mass 0.020 kg), B (mass 0.030 kg) and C (mass 0.050 kg) are approaching the origin as they slide on a frictionless air table. The initial velocities of A and B are given in the figure. All three spheres arrive at the origin at

the same time and stick together. What must be the velocity of C to end up moving at 0.50 m/s in the +x-direction after the collision? 3. A 2.00 – kg block is pushed against a spring with negligible mass and force constant k = 400 N/m, compressing it 0.220 m. When the block is released, it moves along a frictionless, horizontal surface and then up a frictionless incline with slope 37.0˚. (a) What is the speed of the block as it slides along the horizontal surface after having left the spring? (b) How far does the block travel up the incline before starting to slide back down?

4. A pulley, with a rotational inertia of 3.7 x 10-2 kg·m2 about its axle and a radius of 7.3 cm, is acted on by a force applied tangentially at its rim. The force magnitude varies in time as F = 0.16t + 0.34t2, with F in newtons and t in seconds. The pulley is initially at rest. At t = 3.2 s what are (a) its angular acceleration and (b) its angular speed?

5. In the figure, a thin horizontal bar AB of negligible weight and length L = 5.4 m is hinged to a vertical wall at A and supported at B by a thin wire BC that makes an angle θ = 57° with the horizontal. A block of weight W = 240 N can be moved anywhere along the bar; its position is defined by the distance x = 1.39 m from the wall to its center of mass. Find (a) the tension in the wire, and the (b) horizontal and (c) vertical components of the force on the bar from the hinge at A.

6. A cubical block of wood, 10 cm on a side, floats at the interface between oil and water with its lower surface 1.50 cm below the interface. The density of the oil is 790 kg/m3. (a) What is the gauge pressure at the upper face of the block? (b) What is the gauge pressure at the lower face of the block? (c) What are the mass and density of

7. An ore sample weighs 17.50 N in air. When the sample is suspend by a light cord and totally immersed in water, the tension in the cord is 11.20 N. Find the total volume and density of the sample?

8. At one point in a pipeline the water’s speed is 3.00 m/s and the pressure is 5 x 10 4 Pa. Find the pressure at the second point in the line, 11.0 m lower than the first, if the pipe diameter at the second point is twice that at the first.