2 questions on Motion along a straight line

In summary, the conversation discusses a physics problem involving motion along a straight line, specifically an object being dropped from a certain height and the time it takes to travel a certain distance. The participants share different approaches and equations to solve the problem, and eventually determine the height from which the object was dropped.
  • #1
nimaim
7
0
Question on "Motion along a straight line"

[edit: finally got the first one already so I erased it ...]

Hey guys, I really appreciate this forum and all that are taking the time to help out. I wish to be part of this community and help out others in the future as well. I had a question on Motion along a straight line.

An object is dropped from a height H above the ground. This free falling object requires 0.952 s to travel the last 46m before hitting the ground. The acceleration of grav. is 9.8 m/s^2. From what height H above the ground did the object fall. (answer in m).

I tried this a couple of times by getting the velocity using d = rt and setting vf = 0 and g = 9.8 and then using the d = vit + 1/2at^2 but again, prob. not the right approach. I think I'm just losing my head with all this physics because I got the harder problems right in this set of problems. If someone could help me on this, I would really appreciate it. I've been trying to get it for an hour now but am still unable to. The thing is, I have to input these answers online, so even if I'm off by a little, I don't know and I get points taken off for each wrong attempt, so I'm trying my best to get them right the first time. Well, thanks in advance guys. Hope to hear from you all.

Any suggestions would be appreciated; I just need some help on as to how to tackle this problem ...
 
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  • #2
You were almost there. Did you use the eqn "d = vit + 1/2at^2" ? where vi is the velocity 46m above the ground and d = 46m and t = 0.952s ?
This woud give vi = 43.65 m/s.

How far does a body need to fall, from rest, under gravity, to reach a velocity of 46.53 m/s ?
Add this height onto the 46m and you're done.
 
  • #3
Fermat,

Thanks a million bud. You just made that problem look insanely easy after I worked on it for so long. I guess my mind just doesn't function the way yours does but I guess I just have to look more closely at the information I have. Thanks again, I got the answer. It's approximately 143.23m.
 

1. What is motion along a straight line?

Motion along a straight line refers to an object's movement in a single direction on a straight path without changing direction or deviating from the path.

2. How is motion along a straight line measured?

Motion along a straight line is measured using distance and time. The speed of an object in motion can be calculated by dividing the distance traveled by the time taken to travel that distance. Velocity, which includes direction, can also be calculated by dividing displacement (change in position) by time.

3. What is the difference between speed and velocity?

Speed is a measure of how fast an object is moving, while velocity includes both the speed and the direction of motion. This means that an object can have the same speed but different velocities if it is moving in different directions.

4. Can an object have a constant speed but varying velocity?

Yes, an object can have a constant speed but varying velocity if it changes direction while moving along a straight line. For example, a car moving in a circular track at a constant speed will have a varying velocity because it is constantly changing direction.

5. How is acceleration related to motion along a straight line?

Acceleration is a measure of the change in an object's velocity over time. In motion along a straight line, an object can accelerate if it changes its speed or direction. Acceleration in the same direction as motion will result in an increase in speed, while acceleration in the opposite direction will result in a decrease in speed or deceleration.

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