physics
posted by Natasha .
An 18yearold runner can complete a 10.0 km course with an average speed of 4.58 m/s. A 50yearold runner can cover the same distance with an average speed of 4.36 m/s. How much later (in seconds) should the younger runner start in order to finish the the course at the same time as the older runner?

ytime = 10km * 1000m/km / 4.8m/s = 2083.3 sec
otime = 10km * 1000m/km / 4.36m/s = 2293.6 sec
difference = 210.3 sec
the youngster can loll around for about 3.5 minutes before taking off. 
a child traveling 5 m/s on a sleed passes her younger brother. if her average acceleratrion in the sledding hill id 2m/s, how fast is the traveling when she passews her oldeer brother 4s later
Respond to this Question
Similar Questions

physics
A runner, beginning at rest, completed a 50 m run with a final speed of 6 m/s. Assuming constant acceleration. a) What was the average speed of the runner? 
algebra
a long distance runer started running a course, running at an average speed of 2 mph. 1.33 hrs later, a cyclist travelde the same course at an average speed of 4 mph. how many hrs after the runner started did the cyclist overtake the … 
physics
An 18yearold runner can complete a 10.0 km course with an average speed of 4.51 m/s. A 50yearold runner can cover the same distance with an average speed of 4.31 m/s. How much later (in seconds) should the younger runner start … 
Physics
An 18yearold runner can complete a 10.0km course with an average speed of 4.48 m/s. A 50yearold runner can cover the same distance with an average speed of 4.18 m/s. How much later should the younger runner start in order to finish … 
physics
Sprinting near the end of a race, a runner with a mass of 70 kg accelerates from a speed of 6 m/s to a speed of 9 m/s in 2 s. (a) What is the runner's average acceleration during this time? 
physics
If a runner travels at a speed of 10 m/s for 5 seconds, stops for a short time then continues on at a speed of 8 m/s for 4 seconds. How long was the runner stopped for if his average speed at the end of the trip is 4 m/s. 
Physics
An 18yearold runner can complete a 10.0km course with an average speed of 4.39 m/s. A 50yearold runner can cover the same distance with an average speed of 4.27 m/s. How much later (in seconds) should the younger runner start … 
physics
An 18yearold runner can complete a 10.0km course with an average speed of 4.53 m/s. A 50yearold runner can cover the same distance with an average speed of 3.91 m/s. How much later (in seconds) should the younger runner start … 
science
A runner whose mass is 49 kg accelerates from a stop to a speed of 6 m/s in 3 seconds. (A good sprinter can run 100 meters in about 10 seconds, with an average speed of 10 m/s.) (a) What is the average horizontal component of the force … 
Physics
An 18yearold runner can complete a 10.0km course with an average speed of 4.39 m/s. A 50yearold runner can cover the same distance with an average speed of 4.27 m/s. How much later (in seconds) should the younger runner start …