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10 Nov 2019

You drive on Interstate 10 from San Antonio to Houston, half thetime at 56 km/h and the other half at 92 km/h. On the way back youtravel half the distance at 56 km/h and the other half at 92km/h.
(a) What is your average speed from San Antonio to Houston?
km/h

(b) What is your average speed from Houston back to SanAntonio?
km/h

(c) What is your average speed for the entire trip?
km/h

(d) What is your average velocity for the entire trip?
km/h

(e) Describe in words the graph x versus t for (a), assuming themotion is all in the positive x direction.


(f) Describe how the average velocity can be found on a graph of xversus t.

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Hubert Koch
Hubert KochLv2
10 Apr 2019

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Related textbook solutions

Physics: Principles with Applications
7th Edition, 2013
Giancoli
ISBN: 9780321625922

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An automobile travels on a straight road for 21 km at 23 km/h. Itthen continues in the same direction for another 21 km at 46 km/h.(a) What is the average velocity (in km/h) of the car during this42 km trip? (Assume that it moves in the positive x direction.) (b)What is the average speed (in km/h)?

In the latest Indian Jones film, Indy is supposed to throw agrenade from his car, which is going 82.0 km/h, to his enemy's car,which is going 125km/h. The enemy's car is 14.6m in front of theIndy's when he lets go of the grenade.



=====>Part A: What is the Vo ? in km/h

If Indy throws the grenade so its initial velocity relative to himis at an angle of 45 ^\circ above the horizontal, what should themagnitude of the initial velocity be? The cars are both travelingin the same direction on a level road. You can ignore airresistance.

Hint: The grenade moves in projectile motion, and convert the twovelocities given in the problem from km/hr to m/s. Being anexcellent student of P2, Indy knows that horizontal range of thegrenade must equal the distance that the enemies car is ahead atthe time the grenade is thrown plus the distance the enemies cartravels while the grenade is in the air. This distance is given byv_rel*t, where v_rel the relative velocity of the enemies carrelative to the Indy's and t is the time in the air.

Solve for time that the grenade is in the air in terms ofv_0.

Use the range equation to get the grenade distance as a function ofv_0

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=====>Part B: What is Vo in km/h?

Find the magnitude of the velocity relative to the earth.

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Ball A is dropped from the top of a building of height H at thesame instant ball B is thrown vertically upward from the ground.First consider the situation where the balls are moving in oppositedirections when the collide. If the speed of ball A is m times thespeed of ball B when they collide, find the height at which theycollide in terms of H and m. Take x = 0 at the ground, positiveupward.

1.1 With two equations, describe the conditions at the collision(position and velocities of the balls).

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