Question

velocity (mph) 40 north 60 north 60 north 40 north 40 west
time (h) 0.5 1 1.5 2 2.5
a b c d e
position change in speed change in direction accelerating?
a to b increased
b to c same
c to d decreased
d to e same
same
changed
irrelevant

Explanation:

Step1: Recall the definition of acceleration

Acceleration is a change in velocity. Velocity is a vector with speed and direction. If either speed or direction changes, there is acceleration.

Step2: Analyze A to B

Speed increases from 40 mph to 60 mph while direction is north. Since speed changes, there is acceleration.

Step3: Analyze B to C

Speed remains 60 mph and direction is north. No change in speed or direction, so no acceleration.

Step4: Analyze C to D

Speed decreases from 60 mph to 40 mph and direction is north. Since speed changes, there is acceleration.

Step5: Analyze D to E

Speed is 40 mph but direction changes from north to west. Since direction changes, there is acceleration.

Answer:

Position	Change in Speed	Change in Direction	Accelerating?
B to C	same	same	NO
C to D	decreased	same	YES
D to E	same	changed	YES