Worksheet: Acceleration Problems Name Solve the following problems by making a list, writing the equation, filling in the equation and then solving the problem. 1. What is the average acceleration of a car driven by Bubba if the car goes from 22.0 miles/hour to 74.0 miles/hour in 8.56s? List Equation Fill in equation Work/Answer a =? vi = 22.0 mi/h vf = 74.0 mi/h t = 8.56s a = vf - vi a = 74mi/h – 22mi/h t 52mi/h 8.56s 8.56s a= 6.07mi/h/s 2. Billy Bob’s four-wheeler will accelerate at 3.0m/s/s. If Billy Bob starts at 5.00mi/h what will be his final speed after 4.00s? List Equation Fill in equation Work/Answer A = 3.0m/s/s a = vf - vi 3.0m/s/s = Vf – 5mi/h 3.0m/s2(4.00s) = Vf – 5mi/h vi = 5.00 mi/h t 4.00s 12.0m/s = Vf – 5mi/h vf = ? 12.0m/s + 5mi/h= Vf t = 4.00s 12m/s + 2.2m/s = 14m/s conversion: 5mi x 1 hour x 1600m = 2.22m/s h 3600s 1 km 3. Darla Mae is going to school in her hometown of Murphy Mississippi and she is driving the family Tractor. How long does it take Darla Mae to go from 0.00 mi/h to her max speed of 43mi/h if she accelerates at a rate of 3.0mi/h/s? List Equation Fill in equation Work/Answer A = 3.0mi/h/s a = vf - vi 3.0mi/h/s = 43mi/h – omi/h 3.0m/h· s = 43mi/h – 0mi/h vi = 0.00 mi/h t t t vf = 43mi/h t = 43mi/h – 0mi/h t=? 3.0m/h· s 14mi/h m/h· s 14s 4. Elroy’s crop duster plain must reach a speed of 120mi/h to take off. If Elroy starts at a rolling speed of 5.00mi/h and accelerates at 7.55ft/s/s, how long must his take-off field be? List Equation Fill in equation Work/Answer Vf = 120mi/h Vf2 = Vi2 + 2ad Vi = 5mi/h A = 7.55ft/s2 D =? (120mi/h)2 = (5mi/h)2 - 2(7.55ft/s2)(d) 14400mi2/h2 = 25mi2/h2 + 15.1ft/s2(d) 14400mi2/h2 - 25mi2/h2 = 15.1ft/s2(d) 13375mi2/h2 = 15.1ft/s2(d) 13375mi2/h2 = d 15.1ft/s2 952mi2/h2 · s2/ft =d D = 0.39mi or 2.0 x 103ft 5. Gertie Figbottom drops and egg from the hayloft in the barn. The egg falling under the influence of gravity will take how long to hit the ground if the hayloft is 5.25 meters high? List Equation Fill in equation Work/Answer D = 5.25 m d = vi + at2 5.25m =(0)(t) + 9.81m/s2(t)2 5.25 = 9.81m/s2(t)2 A = 9.81m/s2 2 2 2 Vi= 0 2(5.25m) =9.81m/s2(t)2 10.50m = t2 9.81m/s2 1.07s2 =t2 √1.07s2 = t 1.03s =t When I divided 9.81m/s2 into 10.5m the meters canceled out and the s2 went to the top 6. If Gertie’s egg hits her husband Claude in the head, what is the speed at which it hits his head? Claude is 6.0ft and 2.0 inches tall. There are 2.54cm in 1.0inches. List Equation Fill in equation Work/Answer Vf = ? Vf2 = Vi2 + 2ad Vf2 = (0)2 - 2(9.81m/s2)(3.37m) Vi = 0 A = 9.81m/s2 Vf2 = 0 + 66.11m2/s2 Vf =√ 66.11m2/s2 Vf = 8.13m/s D = 3.37m To get the distance of 3.37m I subtracted 6ft 2in from 5.25m. First I converted 6ft 2in to inches only and got 74 inches. Next I did the following 74 in x 2.54cm/in and got 188cm which became 1.88m. If you subtract 1.88m from 5.25m you get 3.37m. 7. Jimbo’s suped-up camaro takes 0.0536mi to reach it max speed. If it will average an acceleration at 42.50mi/h/s, what will be his final speed if the initial speed is 0.00 mi/h? List Equation Fill in equation Work/Answer Vf = ? Vf2 = Vi2 + 2ad Vf2 = (0)2 - 2(42.50mi/h·s)(0.0536mi) Vi = 0 A =42.50mi/h·s Vf2 = 0 + 4.556mi2/h·s Vf =√ 16401mi2/h2 Vf = 128mi/h D = 0.0536mi I changed the acceleration unit from mi/h/s to mi/h·s because they are the same thing. Conversion: I converted 4.556mi2/h·s to mi2/h2 by doing the following conversion 4.556mi2/h·s x 3600s/1hour = 16401mi2/h2 8. A car traveling at 120.0 Km/h comes upon Farmer Johnson’s prized 750lb Sow in the middle of the road. If it takes the car 5.55 seconds to come to a complete stop how far from the Sow must the brakes of the car be applied in order to stop 1.0 cm from the Sow? The rate of average rate acceleration is 6.00m/s/s. Note the 750 lbs is not needed, you must find how far the car will go in order to stop, then you will need to add 1cm. You can do this one two ways. List Equation Fill in equation Work/Answer Vi = 120km/h d = Vit + at2 d = 120km/h(5.55s) + (-6.00m/s2)(5.55s)2 d= 666km·s + (-184.815m) T = 5.55s 2 2 h 2 A = 6.00m/s/s or d = 0.185Km + 92.41m Vf2 = Vi2 + 2ad O =(120km/h)2 +2(-6.00m/s2)d d = 185m - 92.42m D = 92.58m So the answer is 92.59m