Question

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.

Answer 1

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