Friction & Vectors

Friction & Vectors

Good Things!

Multiple Choice

Find the net force: 15 N to the right, and another 15 N to the right.

• 0 N Right
• 0 N Left
• 30 N Left
• 30 N Right

Multiple Choice

A car slows down from +32 m/s to +8 m/s in 4 s. The acceleration is 

• 6 m/s/s opposite the motion
• 2m/s/s in the direction of motion
• 8 m/s/s opposite the motion

Multiple Choice

The fastest trains are magnetically levitated above the rails to avoid friction (and are therefore called
MagLev trains...cool, huh?). The fastest trains travel about 250 km in a half an hour. What is their
average speed in km/hour?

• 250 km/hr
• 500 km/hr
• 125 km/hr

Multiple Choice

What direction does friction act relative to motion?

• in the same direction
• in the opposite direction 
• need more information
• depends on the force

Multiple Choice

The force that acts in the opposite direction of motion when two surfaces come in contact. 

• Force
• Friction
• Static
• Kinetic 

Multiple Choice

F_N=100N, F_f=20N

• μ=5.0

• μ=0.2

• μ=1.2

• μ=0.1

Multiple Choice

A box takes 40 N to start moving when the coefficient of static friction is .54. What is the weight of the box? 

• 81 N
• 18 N
• 98 N
• 74 N

Multiple Choice

What is the coefficient of static friction if it takes 44 N of force to move a box that weighs 86 N? 

• 0.78
• 0.51
• 0.78 N
• 0.58 N

Multiple Choice

 What is the force of friction between a block of ice that weighs 950 N and the ground if μ = .12? 

• 65 N
• 226 N
• 175 N
• 114 N

Multiple Choice

Which statement describes a vector?

• It has magnitude but no direction
• It has direction but no magnitude
• It has both direction and magnitude
• It has constant magnitude but no
   direction

Multiple Choice

An airplane accelerates down a runway at 3.20 m/s/s
for 8 s until it finally lifts off the ground.
Determine the velocity at take-off.

• 0.4 m/s
• 25.6 m/s
• 2.5 m/s

Multiple Choice

A _________ quantity is completely described by magnitude alone. A _________ quantity is
completely described by a magnitude with a direction.

• vector, scalar
• scalar, vector

This principle only works with right triangles. The hypotenuse is the side opposite the right angle.

Multiple Choice

What type of triangles do you use the trig ratios with?

• any type
• right triangle
• obtuse triangle
• acute triangle

Multiple Choice

What leg is considered the hypotenuse?

• Any side
• the side opposite the smallest angle
• the side opposite the right angle
• the side opposite the shortest leg

Multiple Choice

• 20.35
• 12.72
• 14.99
• 21.83

Multiple Choice

• 6.99

• 6.33

• 13.59

• 7.83

Multiple Choice

Find the measure of the missing angle.

• 64^o
• 26^o
• 61^o
• .008^o

Multiple Choice

Vector F in the y-component is ....

• F sin 30^o

• F cos 30^o

• F cos 60^o

• F tan 30^o

Multiple Choice

Vector F in the x-component is ....

• F sin 30^o

• F cos 30^o

• F sin 60^o

• F tan 60^o