Unit 6 Practice Test Flashcards
A system is composed of two particles. One particle is located at (1, 1) and has a mass of 3.4 kg; the second particle is located at (−6.4, 5.8) and has a mass of 5.0 kg. Where is the x-component of the center of mass of the system located?
−3.4
Find the center of mass of the following triangle. Assume the triangle has a constant density of 1.
(2a/3, a/3)
Consider a bar of total mass 30 kg in which two-thirds of its mass is copper and the other third is iron. In addition, two 50-N weights are hanging from the ends of the bar, as shown in the diagram. Where would we tie a string around the bar in order to hang it up from the ceiling and keep it horizontal?
1.5m
A certain fan blade turns at 10,000 rpm. Which of the following is the proper angular velocity of this fan in radians per second?
10,000 * 2pi / 60
A car tire originally rotating at 500 rad / s undergoes a constant angular deceleration of 5.00 rad / s2. Which of the following represents the tire’s angular speed after it has turned through an angle of 628 rad?
sqrt(wo^2 - 2a delta theta)
Consider a wheel rotating counterclockwise as seen from above. Which of the following denotes the direction of the acceleration of Point P if the wheel is speeding up?
-
Tetherball is a game in which two players hit a ball, in opposing directions, that is tied by a rope to a central post. Each player tries to wind the rope around the post in one direction until the ball touches the post itself. The player that does this wins the game. The rope is 2.0 m long and the ball weighs 250 g. The starting player in a particular game holds the ball and hits it with her hand transferring 200 J of energy to the ball. What will be the angular velocity of the ball as it leaves her hand?
20 rad / s
Which of the following masses contributes most to the moment of inertia?
The 1 kg mass
A 48 kg diver stands on the end of a 3 m long diving board. What is the magnitude of the torque that the weight of the diver produces about an axis perpendicular to and in the plane of the diving board through its midpoint?
705 m-N
A student opens a 15.00 kg door by applying a constant force of 40.00 N from a perpendicular distance of 0.90 m from the hinges. If the door is 2.00 m in height and 1.20 m wide, what is the magnitude of the angular acceleration of the door? Assume that the door rotates freely on its hinges.
5.00 rad / s2
A car accelerates uniformly from rest to 20 m / s in 15 s. The wheels have a radius of 0.3 m. What is the angular acceleration of the wheels?
4.43 rad/s^2
Suppose that an engine is rated at 185.00 hp at 4,500 rev / min. How much torque does the engine produce at that rpm?
292.75 m * N
A car is traveling down a highway at a speed of 55 mph. If its wheels have a diameter of 0.70 m, what is their angular velocity? Note: 1 mi = 1.609 km
70 rad / s
A weight of mass m is attached to a rope that is wound around a wheel of radius r. The rope does not slip, no friction is present, and the weight is allowed to drop from rest. After the mass m drops a distance h, what is the kinetic energy of the wheel if the mass has velocity v ?
mgh - 1/2mv^2
Two objects with masses m1 and m2 rotate about a fixed point on massless rods as shown in the diagram below. Which of the following equations describes the magnitude of the total angular momentum of the system?
L = r1m1v1 - r2m2v2
