A golfer rides in a golf cart at an average speed of 3.10 m/s for 23.0 s. She then gets out of the cart and starts walking at an average speed of 1.20 m/s. For how long (in seconds) must she walk if her average speed for the entire trip, riding and walking, is 2.60 m/s

Answer;

= 10.4 sec

Explanation and solution;

Average velocity = Total distance traveled/Total time

Total distance traveled = 3.1 * 29 + 1.2 (T) = 89.9 + 1.2T

where

T = walking time of golfer

Total time = 29 + T

and substituting appropriately into Equation 1

2.6 = (89.9 + 1.2T) / (29 + T)

Simplifying the above,

2.6 (29 + T) = 89.9 + 1.2T

75.4 + 2.6T = 89.9 + 1.2T

1.4T = 14.5

T = 10.4 sec.