A motorist drives north for 35.0 s at 25.0 m/s and then stops for 23.0 s. He then continues north traveling 13.0 m in 2.00 s. (a) What is his total displacement? (b) What is his average velocity (magnitude and direction)?
I am just clueless on this one. I don't even know where to start. The stopping for "23 s and resuming" really confuses me. Pls help.
What are your given equations? If you don't know, google for them.
d – the displacement of the object.
t – the time for which the object moved.
a – the acceleration of the object.
vi – the initial velocity of the object.
vf – the final velocity of the object.
Displacement the object's change in position. So a is asking you to calculate the object's change in position.
Since he has two different velocities, you must calculate two different displacements and add them together.
For the first velocity: time = 35seconds velocity = 25 m/s.
I think the 23 seconds of stopping is intentionally included to confuse you. It doesn't matter to the overall calculation because not moving doesn't influence your displacement calculation.
Thank you Ann!
I had the equations and really was closing in on the answer... (stopping for 23 s is what really got me confused) in either case, the displacement for a) is 888 m !
Now I'll try to calculate (b).
Thank you much!
correct, it just affects the total time.
averagevelocity= displacement/totaltime
To calculate the total displacement, you need to consider the two separate displacements: the first one when the motorist drives north for 35.0 seconds at 25.0 m/s, and the second one when he continues north and travels 13.0 m in 2.00 seconds.
For the first displacement, you can use the equation: displacement = velocity * time.
So, for the first displacement:
Displacement1 = (25.0 m/s) * (35.0 s) = 875.0 m.
For the second displacement:
Displacement2 = (13.0 m/s) * (2.00 s) = 26.0 m.
Now, you can simply add the two displacements together to find the total displacement:
Total Displacement = Displacement1 + Displacement2 = 875.0 m + 26.0 m = 901.0 m.
So, the total displacement is 901.0 m.
To calculate the average velocity (magnitude and direction), you need to consider both the displacement and the total time.
Average Velocity = Total Displacement / Total Time.
Since the time for the first displacement is given as 35.0 seconds and the time for the second displacement (when the motorist stops) is given as 23.0 seconds, the total time can be calculated as:
Total Time = Time1 + Time2 = 35.0 s + 23.0 s = 58.0 s.
Now, you can calculate the average velocity:
Average Velocity = 901.0 m / 58.0 s = 15.52 m/s.
The magnitude of the average velocity is 15.52 m/s, and the direction is north because the motorist is driving north for both displacements.