### Multiple Choice

### 5.1 Vector Addition and Subtraction: Graphical Methods

True or False—We can use Pythagorean theorem to calculate the length of the resultant vector obtained from the addition of two vectors which are at right angles to each other.

- True
- False

True or False—The direction of the resultant vector depends on both the magnitude and direction of added vectors.

- True
- False

- $130\phantom{\rule{thinmathspace}{0ex}}\text{m/s}$ north
- $130\phantom{\rule{thinmathspace}{0ex}}\text{m/s}$ south
- $270\phantom{\rule{thinmathspace}{0ex}}\text{m/s}$ north
- $270\phantom{\rule{thinmathspace}{0ex}}\text{m/s}$ south

- $200\phantom{\rule{thinmathspace}{0ex}}\text{m}$ east
- $200\phantom{\rule{thinmathspace}{0ex}}\text{m}$ south
- $260\phantom{\rule{thinmathspace}{0ex}}\text{m}$ east
- $260\phantom{\rule{thinmathspace}{0ex}}\text{m}$ south

### 5.2 Vector Addition and Subtraction: Analytical Methods

*x*-component of a vector with angle $\theta $ be greater than its y-component?

- ${0}^{\circ}\phantom{\rule{negativethinmathspace}{0ex}}<\theta <{45}^{\circ}$
- $\theta ={45}^{\circ}$
- ${45}^{\circ}\phantom{\rule{negativethinmathspace}{0ex}}<\theta <{60}^{\circ}$
- ${60}^{\circ}\phantom{\rule{negativethinmathspace}{0ex}}<\theta <{90}^{\circ}$

- ${R}_{x}+{R}_{y}=0$
- ${A}_{x}+{A}_{y}=\overrightarrow{\text{A}}$
- ${A}_{x}+{B}_{y}={B}_{x}+{A}_{y}$
- ${A}_{x}+{B}_{x}={R}_{x}$

What is the dimensionality of vectors used in the study of atmospheric sciences?

- One-dimensional
- Two-dimensional
- Three-dimensional

### 5.3 Projectile Motion

After a projectile is launched in the air, in which direction does it experience constant, non-zero acceleration, ignoring air resistance?

- The x direction
- The y direction
- Both the x and y directions
- Neither direction

- ${v}_{y}=0$
- ${v}_{y}=\text{maximum}$
- ${v}_{x}=\text{maximum}$

A ball is thrown in the air at an angle of 40°. If the maximum height it reaches is 10 m, what must be its initial speed?

- 17.46 m/s
- 21.78 m/s
- 304.92 m/s
- 474.37 m/s

- $84.90\phantom{\rule{thinmathspace}{0ex}}\text{m}$
- $96.59\phantom{\rule{thinmathspace}{0ex}}\text{m}$
- $169.80\phantom{\rule{thinmathspace}{0ex}}\text{m}$
- $193.20\phantom{\rule{thinmathspace}{0ex}}\text{m}$

### 5.4 Inclined Planes

For objects of identical masses but made of different materials, which of the following experiences the most static friction?

- Shoes on ice
- Metal on wood
- Teflon on steel

If an object sits on an inclined plane and no other object makes contact with the object, what is typically equal in magnitude to the component of the weight perpendicular to the plane?

- The normal force
- The total weight
- The parallel force of weight

A 5 kg box is at rest on the floor. The coefficient of static friction between the box and the floor is 0.4. A horizontal force of 50 N is applied to the box. Will it move?

- No, because the applied force is less than the maximum limiting static friction.
- No, because the applied force is more than the maximum limiting static friction.
- Yes, because the applied force is less than the maximum limiting static friction.
- Yes, because the applied force is more than the maximum limiting static friction.

A skier with a mass of 67 kg is skiing down a snowy slope with an incline of 37°. Find the friction if the coefficient of kinetic friction is 0.07.

- 27.66 N
- 34.70 N
- 36.71 N
- 45.96 N

### 5.5 Simple Harmonic Motion

A change in which of the following is an example of deformation?

- Velocity
- Length
- Mass
- Weight

The units of amplitude are the same as those for which of the following measurements?

- Speed
- Displacement
- Acceleration
- Force

- ${15}^{\circ}$
- ${45}^{\circ}$
- ${75}^{\circ}$
- ${90}^{\circ}$

- Oscillation will not happen in the absence of friction.
- Oscillation will continue forever in the absence of friction.
- Oscillation will have changing amplitude in the absence of friction.
- Oscillation will cease after a certain amount of time in the absence of friction.

- $0.03\phantom{\rule{thinmathspace}{0ex}}\text{kg}$
- $1.60\phantom{\rule{thinmathspace}{0ex}}\text{kg}$
- $30.7\phantom{\rule{thinmathspace}{0ex}}\text{kg}$
- $63.0\phantom{\rule{thinmathspace}{0ex}}\text{kg}$