Question 1

A vector $$\vec{Z} is $$given by $$\vec{Z} = \vec{A} + \vec{B}. If $$the magnitude of $$\vec{A} is 10 $$units and the magnitude of $$\vec{B} is 7.0 $$units, and the angle between them is $$60^\circ$$, what is the magnitude of $$\vec{Z}$$?

Accepted Answer

$$13.6$$

Question 2

The scalar product of vector $$\vec{A} = 2.00\hat{i} + 2.00\hat{j}$$ and vector $$\vec{B} = 10\hat{i} is$$:

Accepted Answer

$$20.0$$

Question 3

A student starts moving with a constant velocity of $$2.0 m/s $$toward the east. After $$3.0 s$$, the student stops for $$1.0 s$$, then continues with the same velocity for $$2.0 s. $$Which graph best represents the position vs. time for the next $$6.0 s$$?

Accepted Answer

Graph (II)

Question 4

The acceleration of an object as a function of time is given by $$a(t) = (10.0\,	ext{m/s}^2)t$$, where $$t is in $$seconds. If the object is at rest at time $$t = 0.0 s$$, what is the velocity of the object at time $$t = 4.00 s$$?

Accepted Answer

$$80.0\,	ext{m/s}$$

Question 5

While an object is in projectile motion (with upward being positive) with no air resistance:

Accepted Answer

The horizontal component of its velocity remains constant and the vertical component of its velocity changes due to acceleration from gravity.

Question 6

A ball is inside the end of a table of negligible mass. The ball is spun in a circle with a radius $$2.00 m $$making $$7.00$$ revolutions in $$10.0$$ seconds. What is the magnitude of the acceleration of the ball?

Accepted Answer

$$24.6\,	ext{m/s}^2$$

Question 7

A 7.8-kg object is acted on by two forces. One of the forces is $$18.0 N $$acting toward the east. Which of the following forces results in the other force if the acceleration of the object is $$2.0 m/s$^2$$ toward the east?

Accepted Answer

$$-2.0 N$$

Question 8

You push downward on a box at an angle $$25^\circ$$ below the horizontal with a force of $$750 N. If $$the box is on a flat horizontal surface for which the coefficient of static friction with the box is $$0.36$$, what is the mass of the heaviest box you will be able to move?

Accepted Answer

$$150 kg$$

Question 9

A $$0.20 kg $$hockey puck is launched up a ramp that is inclined at a $$30^\circ$$ angle. The coefficient of kinetic friction between the hockey puck and the ramp is $$\mu_k = 0.20. $$The puck's initial speed is $$4.0 m/s. $$How long does it take for the hockey puck to come to a momentary stop (before it slides back down again)?

Accepted Answer

$$0.82 s$$

Question 10

An object of mass $$2.0 kg $$moves along the x-axis. The potential energy curve as a function of position along the x-axis is shown in the figure. If the kinetic energy of the object at the origin is $$12.0 J$$, what will be its kinetic energy at $$x = 2.0 m$$?

Accepted Answer

$$16.0 J$$

Question 11

In the figure, a constant external force $$F = 104 N is $$applied to a $$20 kg $$box, which is on a rough horizontal surface. While the force pushes the box a distance of $$8.00 m$$, the speed changes from $$0.500 m/s to$$ $$2.00 m/s. $$The work done by friction during this process is closest to:

Accepted Answer

$$-1040 J$$

Question 12

Two objects of the same mass move along the same line in opposite directions. The first mass is moving at $$+4.0 m/s. $$The objects collide, stick together, and move at speed $$1.0 m/s in $$the direction of the first mass after the collision. What was the speed of the second mass before the collision?

Accepted Answer

$$-2.0 m/s$$

Question 13

During a collision with a wall, the velocity of a $$0.250 kg $$ball changes from $$20.0 m/s $$toward the wall to $$-16.0 m/s $$away from the wall. If the contact with the wall was $$8.0 ms$$, what was the magnitude of the average force applied to the ball?

Accepted Answer

$$1125 N$$

Question 14

A machinist uses a grinding wheel that is rotating at an angular velocity of $$24$$ rad/s. Upon completing her job, the machinist turns the power off. The wheel decelerates uniformly at $$1.5$$ rad/s$$^2$$ until the wheel stops. In this situation, the time interval of angular deceleration (slowing down) is closest to:

Accepted Answer

$$12 s$$

Question 15

A uniform solid disk of radius $$1.0 m $$and mass $$2.0 kg $$rolls without slipping to the bottom of an inclined plane. The angular velocity of the disk is $$3.35$$ rad/s at the bottom, and its height off the ground is $$2.0 m. $$The moment of inertia of a solid disk is $$I = \frac{1}{2} m r^2$. What is its height off the ground?

Accepted Answer

$$2.29 m$$

Question 16

A potter's wheel, with rotational inertia $$4.0 kg$$·m$$^2$$, is spinning freely at $$40$$ rpm. The potter drops a lump ($$1.0 kg) of $$clay, which sticks at a distance $$0.2 m $$from the rotational axis. If the subsequent angular speed of the wheel and clay is $$32$$ rpm, what is the mass of the clay?

Accepted Answer

$$1.0 kg$$

Question 17

A light triangular plate (1.0 kg) is in a horizontal plane. Three forces, $$F_1 = 6.0$ N, F_2$ = 9.0 N$$, and $$F_3 = 7.0$ N, act on the plate, which is pivoted about a vertical axis through point O. The sum of the torques about the vertical axis through point O, acting on the plate due to the forces, is closest to:

Accepted Answer

$$3.2 Nm$$

Question 18

A traffic light weighing $$100 N is $$supported by two ropes as shown in the figure. The tensions in the ropes are closest to:

Accepted Answer

$$81.3 N$$

Question 19

While spinning down from $$500$$ rpm to rest, a solid uniform flywheel does $$5.1 kJ of $$work. If the radius of the disk is $$1.2 m$$, what is its mass?

Accepted Answer

$$8.4 kg$$

Question 20

A $$2.0 m $$rod of negligible mass connects two very small objects at its ends. The mass of one object is $$0.50 kg $$and the mass of the other is unknown. The center of mass of the system is $$1.2 m $$from the $$0.50 kg $$mass object. What is the mass of the other object?

Accepted Answer

$$0.83 kg$$

PHYS 2204 – Final Exam Study Notes: Mechanics, Energy, and Rotational Motion

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