Skills Workshee Mah Skills Acceleraion Afer you sudy each sample problem and soluion, work ou he pracice problems on a separae shee of paper. Wrie your answers in he spaces provided. In 1970, Don Big Daddy Garlis se wha was hen he world record for drag racing. He sared a res and acceleraed a 16.5 m/s 2 (abou 1.68 imes free-fall acceleraion) for 6.5 s. Wha was Garlis s final speed? Soluion Sep 1: Lis he given and unknown values. Given: acceleraion, a 16.5 m/s 2 ime, 6.5 s iniial speed, iniial v 0 m/s Unknown: final speed, final v? m/s Sep 2: Rearrange he acceleraion equaion o solve for final speed. Sep 3: Inser he known values ino he acceleraion equaion, and solve. final v (16.5 m/s 2 6.5 s) 0 m/s final v 110 m/s Pracice acceleraion ime a final v iniial v a final v iniial v final v a iniial v 1. A bicyclis acceleraes a 0.89 m/s 2 during a 5.0 s inerval. Wha is he change in he speed of he bicyclis and he bicycle? a v final v iniial v 2. A freigh rain raveling wih a speed of 18.0 m/s begins braking as i approaches a rain yard. The rain s acceleraion while braking is 0.33 m/s 2. Wha is he rain s speed afer 23 s? Hol Science Specrum 13 Moion
Mah Skills coninued 3. An auomobile acceleraes 1.77 m/s 2 over 6.00 s o reach freeway speed a he end of an enrance ramp. If he car s final speed is 88.0 km/h, wha was is iniial speed when i began acceleraing? Express your answer in km/h. A child sleds down a seep, snow-covered hill wih an acceleraion of 2.82 m/s 2. If her iniial speed is 0.0 m/s and her final speed is 15.5 m/s, how long does i ake her o ravel from he op of he hill o he boom? Soluion Sep 1: Lis he given and unknown values. Given: acceleraion, a 2.82 m/s 2 iniial speed, iniial v 0.0 m/s final speed, final v 15.5 m/s Unknown: ime,? s Sep 2: Rearrange he acceleraion equaion o solve for ime. final v iniial v a Sep 3: Inser he known values ino he equaion, and solve. 15.5 m/s 0.0 m/s 2.82 m/s 2 15.5 2.82 s Pracice acceleraion ime a a final v iniial v 5.50 s a final v iniial v a a v final v iniial v 4. Once he child in he sample problem reaches he boom of he hill, she coninues sliding along fla, snow-covered ground unil she comes o a sop. If her acceleraion during his ime is 0.392 m/s 2, how long does i ake her o ravel from he boom of he hill o her sopping poin? 5. The sree auomobile wih he greaes acceleraion is he Tempes. I has an acceleraion of 6.89 m/s 2. Suppose he car acceleraes from res o a final speed of 96.5 km/h. How long does i ake he Tempes o reach his speed? Hol Science Specrum 14 Moion
Mah Skills coninued 6. The Impac is he firs commercial elecric car o be developed in over 60 years. During ess in 1994, he car reached a op speed of nearly 296 km/h. Suppose he car sared a res and hen underwen a consan acceleraion of 1.6 m/s 2 unil i reached is op speed. How long did i ake he Impac o reach is op speed? An auomobile manufacurer claims ha is laes model can go from 0 o 90 in 7.5 s. If he 90 refers o 90.0 km/h, calculae he auomobile s acceleraion. Soluion Sep 1: Lis he given and unknown values. Given: ime, 7.5 s iniial speed, iniial v 0.0 km/h final speed, final v 90.0 km/h Unknown: acceleraion, a? m/s 2 Sep 2: Perform any necessary conversions. To find he final speed in m/s, you mus muliply he value for speed by he number of meers in a kilomeer and divide by he number of seconds in an hour. final v 90.0 km 1000 m h 1 km 1 h 1 min 60 min 60 s final v 25.0 m/s Sep 3: Wrie ou he equaion for acceleraion. Sep 4: Inser he known values ino he equaion, and solve. Pracice acceleraion ime a v a 3.3 m/s 2 final v iniial v a v final v iniial v 25.0 m/s 0.0 m/s 25.0 m/s 7.5 s 7.5 s 7. The graviaional force beween Mars and an objec near is surface is much lower han he force beween an objec on Earh s surface and Earh. If a dropped hammer s speed increases from 0.0 m/s o 15.0 m/s in 4.04 s, wha is he acceleraion due o he graviaional force on he surface of Mars? Hol Science Specrum 15 Moion
Mah Skills coninued 8. A figher je landing on an aircraf carrier s fligh deck ha has a lengh of 300.0 m mus reduce is speed from abou 153 km/h o exacly 0 km/h in 2.0 s. Wha is he je s acceleraion? 9. A runner whose iniial speed is 29 km/h increases her speed o 31 km/h in order o win a race. If he runner akes 5.0 s o complee his increase in her speed, wha is her acceleraion? Mixed Pracice 10. A cerain roller coaser acceleraes is cars 6.35 m/s 2 up he firs incline. If his acceleraion happens during he firs 7.0 s of he ride, how much does he speed of he roller coaser cars increase? 11. The solid-fuel rocke boosers used o launch he space shule are able o lif he shule 45 km above Earh s surface. During ha ime, he shule undergoes a nearly consan oal acceleraion of 6.25 m/s 2, so ha is speed increases from res o abou 750 m/s. How long does i ake for he shule o reach his speed? 12. Bonnie Blair currenly holds he world record for skaing 500.0 m in 38.69 s, which she se in 1995. Suppose ha afer she crossed he finish line she coased o a sop on he ice. If her iniial speed was 13 m/s and her acceleraion was 2.9 m/s 2, how long did i ake her o sop? 13. The elevaors in he Landmark Tower, in Yokohama, Japan, are among he fases in he world. They accelerae upward a 3.125 m/s 2 for 4.00 s o reach heir final speed. If hese elevaors sar a res, wha is heir final speed? 14. A ship wih a mass of 5.22 10 7 kg has engines capable of an acceleraion equal o 0.357 m/s 2. Suppose he ship approaches he dock a a speed of 16.98 m/s. How much ime does he ship need o sop? 15. A dog runs wih an iniial speed of 1.5 m/s on a waxed floor. I slides o a sop wih an acceleraion of 0.35 m/s 2. How long does i ake for he dog o sop? Hol Science Specrum 16 Moion
Mah Skills coninued 16. A cerain ype of rocke sled is used o measure he effecs of sudden, exreme deceleraion. The sled reaches a op speed of 320 km/h, hen comes o a complee sop in 0.18 s. Wha is he acceleraion ha akes place in his ime? 17. The building wih he highes occupiable floor is currenly he Sears Tower in Chicago. The op floor of he Sears Tower is 110 sories (436 m) above sree level, and he roof of he ower is 442 m above he sree. Assume a golf ball is hrown downward from he roof of he Sears Tower. Neglecing air resisance, he golf ball acceleraes a 9.8 m/s 2 and lands on he pavemen afer 9.2 s. If he ball s final speed is 93.0 m/s, wha was he speed wih which he ball was iniially hrown? 18. In he heory of plae econics, various segmens of Earh s crus, called plaes, move oward and away from each oher. In one insance, he plae ha consiss of he Indian subconinen drifed from souheasern Africa o is curren posiion in Asia, raveling a a speed of 15 cm/y. This plae collided wih Asia, forming he Himalayan mounain range in he process. Mos of his formaion occurred during he las 1.00 10 7 years, during which ime he Indian subconinen s moion has slowed o abou 5 cm/y. Wha has been he acceleraion, in unis of cm/y 2, of he Indian subconinen during his ime period? Hol Science Specrum 17 Moion