- #1

steve978

- 1

- 0

## Homework Statement

A tennis player hit a serve of 251 km.h

^{-1}in a match. Calculate the Drag Force acting on the tennis ball. Diameter of ball is 6.5cm, density of air is 1.3 kg.m

^{-3}and air viscosity is 1.8x10

^{-5}kg.m

^{-1}.s

^{-1}.

## Homework Equations

Drag Force is: Fd= [itex]\pi[/itex].d

^{2}.C

_{D}.p

_{f}.u

^{2}.1/4

## The Attempt at a Solution

My attempt is to find Reynolds number: Re

_{p}= (p

_{f}u

_{t}d

_{p})/u = (1.3)(903,600,000)(0.065)/0.000018

and then use a graph of drag coefficient against Re

_{p}to find Cd. However my number for Re is 4.24E+13 which is far too large to be correct. Is there something i am doing wrong?