# Speed, a.k.a. Velocity by Dustin Glazier and Josh Patrice, January 1998

## 1.

A car in front of the school goes 30.0 m in 2.35 seconds. What is its speed?
• X = 30 m
• t = 2.35 sec
• V = ?
Try to put those numbers into formulas V = (30 m)/ (2.35 sec) We quickly find that V = 12.8 m/s Josh: Just another useless tedious task setup by the schools to suck away our lives. Dustin: Yeah, but in a fun way!  Table of Contents

## 2.

What time will it take a car going 88 f/s to go 13 feet? (.15s) Here is what you start with:
• X = 13 ft
• t = ?
• V = 88 f/s
Plug those parts in and see what we get. t = (13 ft)/(88 f/s) t = .147727 or .15 seconds Go to:Table of Contents

## 3.

My Jetta can go 92 f in about 1.35 seconds. What is its speed? (68 ft/sec) Here is what you start with:
• X = 92 ft
• t = 1.35 seconds
• V = ?
I'm going to go out on a limb and say "try putting it in a formula" V = (92 ft)/(1.35 sec) V = 68 ft/sec Dustin: You know Josh, it's a very nice Jetta. Josh: Aww, well I wanted an M1 Abrahms tank, but the dealership was all out, so I settled for it. Go to: Table of Contents

## 4.

What is the speed of my Jetta from problem 3 in miles/hour? What is it's color? (46 mph, Red) Here is what you start with:
• X = 92 ft
• t = 3.2 seconds
• V = 68 ft/sec
This is just conversion. As we already know, there are 3600 seconds in an hour and 5280 feet in a mile so we then multiply 68 by 3600 so 68 feet x 3600 sec ------- ---------- 1 sec 1 hour the seconds cancel out leaving feet per hour and then divide by 5280 so 244800 feet x 1 mile ----------- ---------- 1 hour 5280 feet This gives you miles per hour And V = 46 mph Josh: Listen, I was the first person at school with a Red Jetta and it's red because I like it. Dustin: Yeah cause it makes it look like a Raisin! Josh: A WHAT! Dustin: A reallllyyyy cool Raisin? Josh: Dustin, Raisin's aren't red! Dustin: Yeah, but if they were, your car could look like one! Go to:Table of Contents

## 5.

A glazier moves at a rate of 5.6 feet/day. What distance does he go in two weeks? () Here is what you start with:
• X = ?
• t = 2 weeks or 14 days
• V = 5.6 feet/day
PUT THE NUMBERS IN A FORMULA!!!! X = (14 days)(5.6 ft/days) X = 78.4 feet Josh: Do you really move that little? Dustin: No, not always! Josh: I should hope not. Dustin: Sometimes less if I'm close to the refrigerator. Go to: Table of Contents

## 6.

A trucker goes 345 miles in 7.0 hours. What is her speed?
• X = 345 miles
• t = 7 hours
• V = ?
Uhh, use those great formulas and work that physics magic V = (345 miles)/ (7 hours) Math yields the answer of 49 miles per hour or mph. Go to: Table of Contents

## 7.

A space shuttle moves at 3.4 miles/second. What distance does it go in one hour? How many feet?  Here is what you start with:
• X = ?
• t = 1 hr
• V = 3.4 miles/sec
We first break 1 hour down into seconds, there are 60 minutes in an hour and 60 seconds therefore 3600 seconds in 1 hour. Josh: And how many people wasting their time on this web page? Dustin: Just us two, Josh. Plug those parts in and see what we get. X = (3600 sec)(3.4 miles/sec) X = 12240 miles However, Mr. Murray seems hell bent on using feet, so we must convert Now, there are 5280 feet in a mile, so (12240 ft)(5280 ft/ mile) And X = 64627200 feet or 6.5 x 107feet Go to: Table of Contents

## 8.

A car moving 44 feet/second takes what time to travel 16 feet? (.36 s) Here is what you start with:
• X = 16 ft
• t = ?
• V = 44 ft/s
Well let's find time: Dustin: 10:45 Josh: No, moron. The time it takes to travel 16 feet! Dustin: Oh, yeah. V = X/t (44) = (16)/t t = (.36s) Go to: Table of Contents

## 9.

What speed must you average to go 280 km in 3.0 hours(93 km/h) Here is what you start with:
• X = 280 km
• t = 3.0 hrs
• V = ?
Dustin: This problem is quite simple. Josh: All the problems are quite simple. Dustin: Uhh, yes but this one is even simpler! V = (280)/(3.0) V = (93 km/h) Go to:Table of Contents

## 10.

A river current moves at 3.2 miles/hour. How many seconds will it take you to drift 45 feet? (Convert to feet/second first)(9.6 s) Here is what you start with:
• X = 45 ft
• t = ?
• V = 3.2 mi/h
First, let's convert the velocity to feet/seconds. As we learned before, so 3.2 miles x 1 hour ------- ---------- 1 hour 3600 sec the hours cancel out leaving miles per second and then divide by 5280 so 3.2 miles x 5280 feet ----------- ---------- 3600 sec 1 mile This gives you feet per second And V = 4.69 ft/sec t = (45)/(4.69) t = (9.6s) Table of Contents

## 11.

Convert 45 miles/hour to Feet/second? (66 f/s) If this has begun to look familiar to you, you're not alone so 45 miles x 1 hour ------- ---------- 1 hour 3600 sec the hours cancel out leaving miles per second and then divide by 5280 so 45 miles x 5280 feet ----------- ---------- 3600 sec 1 mile This gives you feet per second (66 f/s) Josh: Boy I wish I had that tank. Dustin: You are a small, small man. And you have my pity, farewell. Go to: Table of Contents

## 12.

Convert 60 km/hour to m/s? (17 m/s) Boy oh boy another conversion problem! all right 60 kilos x 1 hour ---------- --------- 1 hour 3600 sec this gives us km/sec so 60 kilos x 1000 meters ---------- -------------- 3600 sec 1 kilo thus giving us m/s. In fact this gives us (17m/s). Josh: Dustin?! Dustin?! Where have you gone? I feel so alone. Go to: Table of Contents

## 13.

Convert 80 feet/second to m/s?(24 m/s) Josh: Dustin? Dustin: Yes. Josh: Where have you been? Dustin: That is none of your concern little boy. And I'll thank you to stay out of my personal affairs. Josh: How do we do this problem? Dustin: The kids should just use their magical powers to make it wind up to be 24m/s. Josh: Well, you heard the man. Go to: Table of Contents

## 14

A car in front of the school travels 15 feet in .38 seconds. What is its speed in m/s?(12 m/s) Here is what you start with:
• X = 15 ft
• t = .38 sec
• V = x
Hey kids, guess what. We need to convert this bad boy into m/s. V = 15 ft x 9.8 m --------- -------- .38 sec 32 ft So, this leaves us with 12.09m/s Go to: Table of Contents

## 15

A satellite travels at 5.4 miles in 3.2 seconds. What is its speed in miles/hour?(6075 mph) Here's what we have:
• X = 5.4 miles
• t = 3.2 sec
• V = x
Simply multiply 5.4 by 3600 to obtain hours. Then, V = (19440)/(3.2) V = (6075 mph) Josh: Hey, Dustin, it's done! Dustin: What's done? Josh: The physics page. Dustin: Cool. So what do we need to finish? Josh: Nothing other than 4 months of late physics homework, the page is done. Dustin: Cool. So what do we need to finish? Josh: NOTHING,THE PAGE IS DONE!!! Dustin: Cool. So what do we need to finish? Josh: NO, YOU DON'T UNDERSTAND, IT'S ALL DONE!!! Dustin: What, what's done? Josh: THE BLOODY WEB PAGE!!!! Dustin: We did a web page? Josh: Who's on the what now? Dustin: Oh, yeah! Go to: Table of Contents