The drag coefficient = 0.354
The mass of car = 1200 kg
rolling resistance = 180 N
Air density = 1.181 kg m^-3
Frontal area = 1.88 m^2
What is the deceleration at a speed of 82 km h^-1 when the car is taken up to high speed and then allowed to coast down on a level road.
Deceleration = (net backwards force) / mass
82 km/h = 22.78 m/s
Air drag force = (1/2)*(density)*(frontal area)*V^2
= (0.5)*(1.181)*(1.88)*(22.78)^2
= 576 N
Rolling resistance = 180 N
deceleration = (576+180)/1200 = 0.63 m/s^2
To calculate the deceleration of the car, we need to use the equation:
deceleration = (force of drag + force of rolling resistance) / mass of the car
First, let's calculate the force of drag. The drag force can be calculated using the equation:
force of drag = (1/2) * drag coefficient * air density * frontal area * velocity^2
where the velocity is in m/s. We need to convert the speed from km/h to m/s by dividing it by 3.6:
velocity = 82 km/h = (82 * 1000) / 3600 = 22.78 m/s
Now, we can calculate the force of drag:
force of drag = (1/2) * 0.354 * 1.181 * 1.88 * (22.78)^2
Next, let's calculate the force of rolling resistance, which is given as 180 N.
Now, substitute the values into the equation for deceleration:
deceleration = (force of drag + force of rolling resistance) / mass of the car
deceleration = (force of drag + 180) / 1200
Calculate the numerator:
numerator = force of drag + 180
Finally, substitute the values into the equation for deceleration:
deceleration = numerator / 1200
Now, calculate the deceleration and round it to the appropriate number of significant figures.