Answer:
Answer:
15.67 seconds
Explanation:
Using first equation of Motion
Final Velocity= Initial Velocity + (Acceleration * Time)
v= u + at
v=3
u=50
a= - 4 (negative acceleration or deceleration)
3= 50 +( -4 * t)
-47/-4 = t
Time = 15.67 seconds
First, you have to write what you know:
V = 3.60 m/s
D = ?
T = 18.4 s
Next, you plug everything into this formula:
V = D/T
3.60 m/s = ?/18.4 s
Then, you multiply 3.60 m/s and 18.4 s
D = 66.24 m
Note that Speed = Distance/Time.
1st trip:
Distance = 30 mi
Time = 30 min = 0.5 h
Speed = 30/0.5 = 60 mi/h
2nd trip:
Distance = 50 mi
Time = 1 hour
Speed = 50 mi/h
3rd trip:
Distance = 30 mi
Time = 30 min = 0.5 h
Speed = 30/0.5 = 60 mi/h
Average speed = (60 + 50 + 60)/3 = 56.7 mph
The closestanswer is 55 mph
Answer: 55 mph
The doctor's average speed for the whole trip is 75 km per hour. His average velocity for the whole trip is zero.