Vectors & Relative MotionMultiple-Choice Practice Problems

Question #1In a diagram, the length of a vector arrow represents the

a)type of vector. b)direction of the vector. c)magnitude of the vector. d)cause of the vector.

Question #2Which of the following quantities used to describe motion is an example of a vector quantity? a) distance b) speed c) time d) average velocity

Question #3A vector remains unchanged a) if it is moved in any direction. b) only if it is moved parallel to its

original direction. c) only if it is rotated perpendicular

to its original direction. d) only if it is not moved.

Question #4Which of these displacements will be equal to d1 +d2 +d3?a) d3+d4+d1 b) d2+d1+d3c) d2+d4+d3d) d4+d3+d1

Question #5Which of the following represents the vector resulting in the subtraction of d2 −d1 shown in the figure?

Question #7If vectors are moved according to the rules of the triangle method of vector addition, then the resultant vector is drawn a) from the tail of the first vector to the tail

of the last vector. b) from the tail of the first vector to the tip

of the last vector. c) from the tip of the first vector to the tail

of the last vector. d) from the tip of the first vector to the tip of

the last vector.

Question #8A skier slides onto a horizontal patch of slushy snow at velocity vskier, and slows to a constant speed without changing direction. Which of the following could be the skier’s resulting velocity? a) -3vskier

b) +(1/4) vskier c) -(1/5) vskier

d) all of the above.

Question #11In a school playground, a child runs 5 m in the x direction and then 2.0 m in the –y direction. Which of the following represents the magnitude of the child’s displacement?

Question #12In the triangle below, what does Θequal?

Question #13The projection of a vector along the axes of a coordinate system isa) a component of the vector. b) a tangent of the vector. c) the resultant of the vector. d) the magnitude of the vector.

Question #14The components of a vector are

a) each equal to half the magnitude of the vector.

b) independent of the orientation of the vector.

c) perpendicular. d) vector quantities.

Question #15A vector that has components that lie along the -x-axis and the +y-axis is oriented at angle A measured counterclockwise from the +x-axis. Which of these ranges gives values of A? a) 0°<A<90°b) 90°<A<180° c) 180°<A<270° d) 270°<A<360°

Question #16If the x-component of B equals the magnitude of B, then

a) both components are equal. b) By equals B2+Bx

2 c) By equals zero. d) By lies along the y-axis.

Question #17Which of the following is a frame of reference for measuring motion?

a) coordinate system b) diagram c) graph d) none of the above

Question #18-22 StoryIn a circus parade, a clown standing on a float moving at a constant forward speed drops a fake dumbbell. A child in the bleachers on the sidewalk observes the dumbbell falling.

Question #18Who would observe the dumbbell falling straight down?

a) The clown onlyb) The child onlyc) The clown and the childd) Neither

Question #19Who would observe the dumbbell falling backward?

a) The clown onlyb) The child onlyc) The clown and the childd) Neither

Question #20The clown and child would agree about which of the following?

a) The time for the dumbbell to fallb) The distance the dumbbell fallsc) The initial velocity of the

dumbbelld) All of the above

Question #22If the float has a velocity of +vfloat with respect to the ground, what is the velocity of the child with respect to the clown?

a) 0b) +vfloat c) -vfloat d) (+vfloat –vchild)/2

Question #23The velocity of a passenger relative to a boat is -vpb. The velocity of the boat relative to the river is +vbr. The velocity of the river to the shore is +vrs. What is the velocity of the passenger relative to the shore? a) -vpb+vbr +vrs b) vpb - (vbr + vrs) c) -(vpb + vbr + vrs) d) vpb+vbr+vrs

Question #24A car traveling at the speed limit has velocity +vcar with respect to the road. You are in another car traveling in the opposite direction at the speed limit with respect to the road. As the first car approaches you, what is its velocity relative to you?a) +vcar

b) vcar

c) +2vcar

d) -2vcar

ANSWERS1: C 2: D 3: B 4: B 5: D 7: B 8: B

11: D 12: A 13: A 14: C 15: B 16: C 17: A

18: A 19: D 20: D 21: C 22: B 23: A 24: C