A jogger runs at an average speed of 4.20 mi/h. (a) how fast is she running in m/s? (report your answer to the correct number of
significant figures.) 1.88 m/s (b) how many kilometers does she run in 33.0 min? (report your answer to the correct number of significant figures.) 3.72 km (c) if she starts a run at 11:15 a.m., what time is it after she covers 4.84 × 104 ft? : p.m.
a) How fast is she running in m / s? The first thing you should know for this case is the following conversion 1mi = 1609.34m 1h = 3600s Applying the conversion 4.20 (mi / h) * (1609.34 / 1) (m / mi) * (1/3600) (h / s) = 1.88 m / s answer She is running 1.88 in m / s
(b) how many kilometers does she run in 33.0 min? By definition, the distance equals the speed by time d = v * t Also, 1min = 60seconds 1 km = 1000 meters. We have then d = (1.88) * (33) * (60) * (1/1000) = 3.72 Km answer she run 3.72 Km in 33.0 min
(c) if she starts a run at 11:15 a.m., what time is it after she covers 4.84 × 104 ft? : p.m. The first thing we need to know is the following conversion 1Km = 3280.84 feet We have then 3.72 (Km) * (3280.84 / 1) (feet / Km) = 12204.73 feets I have the following rule of three we can know how long she travels 4.84 × 104 ft 12204.73 feets ----> 33 min 4.84 * 10 ^ 4 feets ----> x Clearing x: x = ((4.84 * 10 ^ 4) / (12204.73)) * (33) = 131 min 131 min = 2:11:00 hours she starts a run at 11:15 a.m. she finishes at 1:26 p.m. answer it is 1:26 p.m when she covers 4.84 × 104 ft
