A race driver has made a pit stop to refuel. After refueling, he leaves the pit area with an acceleration whose magnitude is 6.0m/s 2 . After 4.0s he enters the main speedway. At the same instant, another car on the speedway and traveling at a constant speed of 70 m/s overtakes and passes the entering car. If the entering car maintains its acceleration, how much time is required for it to catch the other car?
 👍
 👎
 👁
 ℹ️
 🚩
1 answer

Measure time from the instant the pit car (#1) enters the speedway. When that car enters, its speed is 6.0 * 4.0 = 24 m/s, and it is still accelerating.
X1 = Vo t + (1/2) a t^2 = 24t + 3 t^2
For the constantspeed car,
X2 = 70 t
The time required for car 1 to catch up with car #2 is given by
X1 = X2
24t + 3 t^2 = 70t
46t = 3 t^2
t = 0 or 46/3 s
We are not interested in the t=0 solution, therefore
t = 15.3 s 👍
 👎
 ℹ️
 🚩
answered by drwls
Answer this Question
Related Questions

Physics
The speed limit in a school zone is 40km/h. A driver traveling at this speed sees a child run into the road 13m ahead of his car. He applies the breaks, and the car decelerates at uniform rate of 0.8m/s². If the driver's reaction times is 0.25s, will the
 asked by Majiri

Calculus
Given that g(t) is continuous, find the value of c: g(t) = {ct + 2 if t <  2; cos(pit/2) if t >= 2. a. c = 3/2 b. c = 1/2 c. c = 0 d. c =  2 e. none of the above
 asked by Sarah

english
Which sentence demonstrates correct placement of an adverb modifying an adjective?(1 point) Responses The organized drawer made her smile perfectly. The organized drawer made her smile perfectly. The energetic dog very barked. The energetic dog very
 asked by v

L.A.Help!!!!!!
Which sentence is a main idea of "Why Leaves Turn Color in the Fall"? A. Leaves stop making chlorophyll add summer ends. B. Leaves reflect the colors of corn, pumpkins, and cranberries in the fall. C. Photosynthesis begins in the fall. D. Longer days and
 asked by blue

Physics
The “reaction time” of the average automobile driver is about 0.7 s. (The reaction time is the interval between the perception of a signal to stop and the application of the brakes.) If an automobile can slow down with an acceleration of 12 ft/s^2
 asked by Babygirl

physics
a driver in a car traveling at a speed of 21.8 m/s sees a cat 101m away on the road. How long will it take for the car to accelarate uniformly to a stop in exactly 99m?
 asked by vanessa

Physics
A race car can be slowed with a constant acceleration of 11 m/s^2 a. If the car is going 55 m/s, how many meters will it travel before it stops? b. How many meters will it take to stop a car going twice as fast? I know you use the equation d = Vit +1/2
 asked by Priscilla

Mathplease check!
1. Which of the following are continuous random variables? (select all that apply) a. The distance a person has walked in a day b. How many glasses of water a person consumes in a day c. The number of steps a person has walked in a day d. The time it takes
 asked by cat

Physics
A sprinter starts from rest in a 100meter race, accelerates to his full running speed of 10.3 m/s in 1.15 seconds (assume constant acceleration) and continues at that speed for the rest of the race. (a) How far did he run before attaining his full speed?
 asked by Phil

physics
A driver traveling at 25 mph in a school zone can brake to an emergency stop in 8 ft. Under similar conditions, what would be the braking distance if the car were traveling at 40 mph?
 asked by Jose

Chemistry
Which activity gives access to natural resources but might lead to problems such as sinkholes? (1 point) O traditional hunting O fracking O openpit mining O commercial agriculture Some contaminants enter the water from commercial farming, while other
 asked by Rina

Geometry
At a campground, a rectangular fire pit is 5 feet by 4 feet. What is the area of the largest circular fire that can be made in this fire pit? Use 3.14 for π. Round to the nearest square inch.
 asked by Jose

Math
Four hours after the start of a 600 mile auto race, a driver's velocity is 150 miles per hour as she completes the 352nd lap on a 1.5 mile track a) find the drivers average velocity during the first four hours of the race. b) let f(x) represent the
 asked by John

physics 1
Problem 1) I don't understand how they got the answers for A) and B) : Ima Rushin can travel from Milwaukee Avenue to the school entrance gate at a constant speed of 22.5 m/s when the lights are green and there is no traffic. On Wednesday, Ima is stopped
 asked by Dina

Physics Part A HELP!!
4.) In coming to a stop, a car leaves skid marks 80m long on the highway. Assuming a DEceleration of 7.00 m/s^2 (m/s/s), estimate the speed of the car just before breaking. 6.) A car traveling @ 90km/h strikes a tree. The front end of the car compresses
 asked by Jess

Math
The results of a car race are shown. Determine who drove the fastest. Explain. Driver Laps Time (min) Cutwrite 35 84 Evans 42 96.6 Loza 38 102.6
 asked by Anonymous

math
Melissa collected three kinds of autumn leaves when she was out walking todayelm, maple and oak. She has 2 times as many maple leaves as elm leaves and 5 times as many oak leaves as elm leaves. Altogether she has 32 leaves how many of eash kind does she
 asked by rylan

physics
The figure shows the velocity of a solarpowered car as a function of time. The driver accelerates from a stop sign, cruises for 20 at a constant speed of 60 , and then brakes to come to a stop 40 after leaving the stop sign.
 asked by Anonymous

physics help please!
A race car is one lap behind the lead race car when the lead car has 57 laps to go in a race. If the speed of the lead car is 66.2 m/s, what must be the average speed of the second car to catch the lead car just before the end of the race (i.e., right at
 asked by Amanda

physics
a 1000kg car is travelling with a speed of 33.3m/s2 when the driver saw an intersection 30m away. how much force is needed to stop the car right away?
 asked by jericho
Still need help?
You can ask a new question or browse existing questions.