Secure l https://www.webassignanet/web/student/Assignment Responses/last?dep-156
ID: 1595012 • Letter: S
Question
Secure l https://www.webassignanet/web/student/Assignment Responses/last?dep-15675357 (c) Determine the magnitude of the acceler ation of the elevator. Need Help? a Show My Work ro O -10 points serPSE9 6 P027 The of a sports My Notes o Ask teac mass car is 1100 kg. The shape of the car is such that the drag c is 0.250 and the frontal area is 2.30 m2. Neglecting all other sources of friction, calculate the initial acceleration of the car, it has been traveling at 115 km/h and is now shirted to neutral and is allowed to coast. (Take the density of air to be 1.295 kg/m3.) m/s2 Need Help? LRead It Show My Work opeenala?Explanation / Answer
The drag coefficient, Cd = 0.25
The mass of car, m = 1100 kg
The density of air, = 1.295 kg/m^2
The speed of sport car, u = 115 km/h = 115*5/18 = 31.94 m/s
The frontal area A = 2.3 m^2
The drag force is given by the formula
f_drag = -½ v² A Cd
But we have a relation between the force and acceleration as
a = f/m
==> a = -½ v² A Cd/m
a = -½ (1.295)(31.94)²(2.3)(0.25)/1100
a = -0.345 m/s²
therefore the deceleration is 0.345 m/s²