http://www.ck12.org Chapter 2. One-Dimensional Motion
c. What is the greatest height reached by the man above the ground? (Hint: this should be greater than 20
m. Why?
d. What is the distance between the helicopter and the man three seconds after he lets go of the rope?- You are speeding towards a brick wall at a speed of 55 MPH. The brick wall is only 100 feet away.
a. What is your speed in m/s?
b. What is the distance to the wall in meters?
c. What is the minimum acceleration you should use to avoid hitting the wall? - What acceleration should you use to increase your speed from 10 m/s to 18 m/s over a distance of 55 m?
- You drop a rock from the top of a cliff. The rock takes 3.5 seconds to reach the bottom.
a. What is the initial speed of the rock?
b. What is the magnitude (i.e.,numerical value) of the acceleration of the rock at the moment it is dropped?
c. What is the magnitude of the acceleration of the rock when it is half-way down the cliff?
d. What is the height of the cliff?
Answers to Selected Problems
- a. 7.7 m/s^2 b. 47 m, 150 feet c. 34 m/s
- a. 1.22 m b. 4.9 m/s c. 2.46 m/s d. -4.9 m/s
- b. 1 second c. at 2 seconds d. 4 m
- a. 250 m b. 13 m/s, -13 m/s c. 14 s for round trip
- Let’s say we can jump 20 feet (6.1 m) in the air.,Then, on the moon, we can jump 36.5 m straight up.
6.−31m/s^2 - 23 m/s b. 3.6 seconds c. 28 m d. 45 m
- 25 m/s b. 30 m c. 2.5 m/s^2
- 2.04 m/s^2
- a.v 0 =0 b. 10 m/s^2 c.−10 m/s^2 d. 60 m
Summary
In these lessons students will learn the fundamentals of motion in one dimension, graphing position, velocity and
acceleration vs time and using the kinematic equations to solve problems.