# What is 1d motion: Definition and 25 Discussions

10. ### Find time to reach ball. 1D motion

Homework Statement basket ball player throws a ball up in the air and the ball travels 3.2meters before stopping. if the basketball player jumps .5 seconds after throwing the ball. what velocity does he need to reach the ball. Homework Equations vf^2=v1^2+2as sf=si+vot+1/2at^2 vf=vi+aot...
11. ### Solve 1D Motion Questions: Determine Velocity, Max Height, Time Req.

Homework Statement a rock is thrown nearly vertical upward from the edge of a tall building of height H. it just misses the edge of the building on the way down and strikes the ground T seconds after being thrown. given H, T determine the initial velocity of the rock the max height it reaches...
12. ### Solve 1D Motion: Find Distance, Time, Velocity

Homework Statement at the instant the traffic light turns green, s starts from rest and accels at a_s. at the same time k passes s with constant velocity v_k. given a_s, v_k, find distance before the cross again time it takes to do so velocity of s at this point plot the position as...
13. ### Solving 1D Motion Question with x>0, v<0, a>0

Homework Statement Give example of a motion where x>0, v<0, a>0 at a particular instant. x-->Position v-->Velocity a-->Acceleration Homework Equations I thought I had to give an example such as a car, ball etc. But the answer says: x(t) ie; position for time t; given by...
14. ### 1D Motion - Position as a Funtion of Time

All, I am reviewing for a comprehensive exam and am extremely weak on 1D Motion. Can you please help me out? A lab cart travels along the x-axis and its position as a function of time is given by the following expression: x(t)= 6m - (8 m/s)t + (1 m/s2)t2 1. Displacement of cart during time...
15. ### 1D motion question, help please

Homework Statement A car making a 94-km journey travels 39 km/h for the first 47 km. How fast must it go during the second 47 km to average 51 km/h? Homework Equations The Attempt at a Solution
16. ### 1D Motion Displacement, Velocity

All are true false but need help on all of them thanks in advance 1)Knowing the position and velocity of a particle allows its future position to be predicted even if its acceleration is unknown. 2)Instaneous velocity is the derivative of the displacement time function. 3)If the...
17. ### I can't seem to understand 1d motion.

1. The problem statement I am studying for an upcoming test and I am having a lot of trouble relating velocity, acceleration, and displacement vs time. Given a position vs time function: x(t) = 6m - (8m/s)t + (1m/s^2)t^2 I cannot for the life of me understand how to find any instantaneous...
18. ### Need help with two 1d motion problems

Problem 1 A commuter train travels between two downtown stations. Because the stations are only 1.00 km apart, the train never reaches its maximum possible cruising speed. During rush hour the engineer minimizes the travel interval Δt between the two stations by accelerating for a time interval...
19. ### Very beginner physics 1D motion question

[SOLVED] Very beginner physics 1D motion question! Homework Statement Two cars move in opposite directions toward each other on a level, straight, one-lane road. When both drivers begin to brake, their front bumpers are 275 meters apart. The smaller car is initially moving at 25.0 m/s and the...
20. ### Solving 1D Motion: How Fast Must a Police Car Go to Catch a Holdup Car?

Homework Statement A police car leaves in pursuit of a holdup car 0.50 h after the latter has left the scene of the crime at 120 km/h. How fast must the police car go if it is to catch up with the holdup car in 1.00h? Homework EquationsI'm thinking Vf=Vo+at? i must be wrong, I can't seem to...
21. ### Solving 1D Motion Problems with Fun: Average Rate and Time Calculations

FUN 1d motion prob--help Homework Statement The figure (http://img471.imageshack.us/my.php?image=picprobfd5.png) shows a general situation where a stream of people attempt to escape through a door that is closed. The people move toward the door at a speed of v = 3.50 m/s, are each d = .25 m...
22. ### Frictional Forces and 1D Motion

INTRODUCTION: This is a problem from my Introduction to Physical Science class using "Conceptual Physics" 10th Ed.by Paul G. Hewitt EXACT PROBLEM: "The coefficient of kinetic friction between a rubber tire and a wet concrete road is 0.5." PROBLEMS FACED: a) Find the minimum time in...
23. ### Analyzing 1D Motion of a Particle in a Potential

Consider the one dimensional motion of a particle in the potential V(x)=D(e^{-2ax}-2e^{-ax}). I'm supposed to obtain the expressions for x as a function of time separately for the cases that the total energy E is positive, zero or negative. I have used \frac{1}{2}m\dot{x}^2 + V(x) -...
24. ### Low Level Physics Problem 1D Motion

47. A rock is dropped from a sea cliff and the sound of it striking the ocean is heard 3.4s later. If the speed of sound is 340 m/s, how high is the cliff? Could somebody map this one out for me, it isn't making any sense.
25. ### Calculating Original Speed and Acceleration in 1D Motion

The question goes as follows: A truck covers 40.0 m in 8.50 s while smoothly slowing down to final speed +2.40 m/s. Find the original speed Find the acceleration Now, I tried a couple things for the speed, I tried 40/8.50, and I tried (4.71/2.40) and both turned out to be wrong. Not...