changhyeon

I have three questions about US history in1989.

1.How does the increasing globalization of society effect how people see themselves in 1989?

How do the ending of the Cold War and pro-democracy protest around the world effect how Americans see their place in the world in 1989?

How do the rapid social changes of 1989 effect how minority groups see themselves in the U.S.?

How does the increasing globalization of society effect how people see themselves in 1989?

A figure skater is spinning on ice with his arms outstretched. He then pulls his arms

inward in preparation for a jump. Which of the following quantities is/are conserved as

as he does this? Ignore the friction between the skates and the ice.

I. His angular momentum

II. His angular velocity.

III. His rotational kinetic energy.

A. I only.

B. II only.

C. III only.

D. More than one of these is conserved

Which of the following quantities does NOT affect the angular momentum of a body?

A. Its momentum.

B. Its angular velocity.

C. Its moment of inertia.

D. The axis of rotation.

E. All of the above affect the angular momentum.

An object has several forces acting on it. One force is F⃗ =αxyi^, a force in the x-directionen whose magnitude depds on the position of the object. The constant is α=2.00N/m2. The object moves along the following path: (1) It starts at the origin and moves along the y-axis to the point x=0,y=1.50m; (2) it moves parallel to the x-axis to the point x=1.50m, y=1.50m; (3) it moves parallel to the y-axis to the point x=1.50m, y=0; (4) it moves parallel to the x-axis back to the origin.

Question 1: Calculate the work done on the object by F⃗ for leg (1) of the path and for the complete round trip.

Question 2:Calculate the work done on the object by F⃗ for leg (2) of the path.

Question 3: Calculate the work done on the object by F⃗ for leg (3) of the path.

A uniform solid ball rolls without slipping down a an inclined ramp at an angle β with respect to the ground. What is the magnitude of the acceleration of the ball's center of mass?

A. 5/7 g sin β

B. 5/7 g cos β

C. 2/3 g sin β

D. g sin β

A force of 10 N is applied to the end of a long rectangular object, which is at rest. Two students carefully calculate the torque from that force on the object. The first student finds that the torque is 5 Nm while the other student finds that it is 7 Nm. Assuming that they have not made any mistakes in their calculations what might account for the difference?

A. The dot product of the torque vector and the force vector is zero.

B. Torque is always a matter of opinion.

C. Torque is measured about a specific point and the students have chosen different points.

D. One student views the torque from the left while the other views the torque from the right.

A uniform solid ball rolls without slipping down a an inclined ramp at an angle β with respect to the ground. What is the magnitude of the acceleration of the ball's center of mass?

A. 5/7 g sin β

B. 5/7 g cos β

C. 2/3 g sin β

D. g sin β

The center of mass of a collection of particles acted upon by a external forces moves as though all the mass were concentrated at that point and acted upon by a force equal to the ____ of all the external forces.

A. average

B. largest

C. vector sum

D. vector average

In an elastic collision what quantities are conserved? (select the best answer)

A. only the vector sum of all momenta

B. both the total potential and the total kinetic energy

C. both the vector sum of all momenta and the total kinetic energy

D. only the total potential energy

E. only the total kinetic energy

The center of mass is

(select all that apply)

A. located at the geometric center of a homogeneous body.

B. can never be located outside of the body.

C. is located on the symmetry axis of a symmetrical object.

D. is always in the middle of the object's surface.

For a rotating body, which of the following statements best describes the relationship between the linear acceleration and the angular velocity and acceleration for a point at a fixed radius?

A. The radial component of the linear acceleration is concerned with the change in speed of the body and is proportional to the square of the angular velocity, while the tangential component of angular velocity is related to the body's change in direction and is proportional to the angular acceleration.

B. The radial component of the linear acceleration is concerned with the body's change in direction and is proportional to the angular acceleration, while the tangential component of angular velocity is related to the change in speed of the body and is proportional to the square of the angular velocity.

C. The radial component of the linear acceleration is concerned with the change in speed of the body and is proportional to the angular acceleration, while the tangential component of angular velocity is related to the body's change in direction and is proportional to the square of the angular velocity.

D. The radial component of the linear acceleration is concerned with the body's change in direction and is proportional to the square of the angular velocity, while the tangential component of angular velocity is related to the change in speed of the body and is proportional to the angular acceleration.

n an elastic collision what quantities are conserved? (select the best answer)

A. only the vector sum of all momenta

B. both the total potential and the total kinetic energy

C. both the vector sum of all momenta and the total kinetic energy

D. only the total potential energy

E. only the total kinetic energy

The center of mass of a collection of particles acted upon by a external forces moves as though all the mass were concentrated at that point and acted upon by a force equal to the ____ of all the external forces.

A. average

B. largest

C. vector sum

D. vector average

At a stable equilibrium point, we have (for one-dimensional motion) that

A. the force is zero and the potential energy is at a

maximum.

B. the force is zero and the potential energy is at a

minimum.

C. the force is at a maximum and the potential energy is zero.

D. the force is at a minimum and the potential energy is zero.

You can find the corresponding force of a potential energy function by

A. taking the negative derivative of the potential energy function with respect to position.

B. taking the positive derivative of the potential energy function with respect to position.

C. taking the negative derivative of the potential energy function with respect to time.

D. taking the positive derivative of the potential energy function with respect to time.

A marksman holds a rifle loosely so that it can recoil freely. He fires a bullet with a mass much less than the mass of the rifle. Which of the following statements is true? (select only one)

A. The magnitude of the bullet's momentum is equal to the magnitude of the rifle's momentum.

B. The force of the bullet on the gun is twice the force of the gun on the bullet.

C. The kinetic energy of the gun is equal to the kinetic energy of the bullet.

D. The recoil velocity of the gun is equal to the velocity of the bullet.

Which of the following are conservative forces? Mark all that apply

A. The force of gravity.

B. The force of a spring.

C. The electric force between two charged objects.

D. The force of kinetic friction.

The momentum of a particle equals...

(select all that apply)

A. the impulse that accelerated it from rest to its present speed.

B. the mass of the particle times its velocity.

C. the kinetic energy divided by the impulse.

D. the mass of the particle times its acceleration.