Engineering, 19.02.2020 05:18 KadaLearns

A driver is traveling at 55 mi/h on a wet road. An object is spotted on the road 450 ft ahead and the driver is able to come to a stop just before hitting the object. Assuming standard perception/reaction time, determine the grade of the road.

Answers: 1

Show answers

Answers

Answer from: carlinryan

G = +/- 0.0583 = +/- 5.83 %

Explanation:

Given:

- Speed of the vehicle V = 55 mi/h

- The spotting distance D = 450 ft

- Assume standard perception/reaction time t = 2.5 s

Find:

Determine the grade of the road. When driver stops just before hitting the object.

Solution:

Step 1:

Determine the distance d traveled for the perception reaction time t:

d = V*t

d = 55*1.467*2.5 = 201.7125 ft

Step 2:

The remaining distance left is the practical stopping distance SD:

SD = D - d

SD = 450 - 201.7125

SD = 248.2875 ft

Step 3:

Calculate the grade G using practical stopping distance SD formula:

SD = V^2 / [ 30(a/g +/-G) ]

(a/g +/-G) = V^2 / 30*SD

G = +/- ( V^2 / 30*SD - a/g )

Where, a = 11.2 ft/s^2 and g = 32.2 ft/s^2 and V = 55 mph

Plug in the values:

G = +/- ( 55^2 / 30*248.2875 - 11.2/32.2 )

G = +/- 0.0583 = +/- 5.83 %

Answer from: Quest

jesus loves you

explanation:

Answer from: Quest

the equation above shows how temperature f, measured in degrees fahrenheit, relates to a temperature c, measured in degrees celsius. based on the equation, which of the following must be true?

a temperature increase of 1 degree fahrenheit is equivalent to a temperature increase of

degree celsius.

a temperature increase of 1 degree celsius is equivalent to a temperature increase of 1.8 degrees fahrenheit.

a temperature increase of

degree fahrenheit is equivalent to a temperature increase of 1 degree celsius.

a) i only

b) ii only

c) iii only

d) i and ii only

Another question on Engineering

Engineering, 04.07.2019 12:10

On a average work day more than work place firs are reorted

Answers: 1

Answer

Engineering, 04.07.2019 18:10

Apipe with an outside diameter of 15 cm is exposed to an ambient air and surrounding temperature of -20°c. the pipe has an outer surface temperature of 65°c and an emissivity of 0.85. if the rate of heat loss from the pipe surface is 0.95 kw per meter of length, the external convective heat transfer coefficient (h) is: (a) 12.5 w/m"k (b) 18.6 w/mk (c) 23.7 w/mk (d) 27.9 w/mk (e) 33.5 w/mk

Answers: 1

Answer

Engineering, 04.07.2019 19:20

At steady state, air at 200 kpa, 325 k, and mass flow rate of 0.5 kg/s enters an insulated duct having differing inlet and exit cross-sectional areas. the inlet cross-sectional area is 6 cm2. at the duct exit, the pressure of the air is 100 kpa and the velocity is 250 m/s. neglecting potential energy effects and modeling air as an 1.008 kj/kg k, determine ideal gas with constant cp = (a) the velocity of the air at the inlet, in m/s. (b) the temperature of the air at the exit, in k. (c) the exit cross-sectional area, in cm2

Answers: 2

Answer

Engineering, 06.07.2019 03:10

List and describe the parts of boxford cnc milling machine with pictures?

Answers: 2

Answer

You know the right answer?

A driver is traveling at 55 mi/h on a wet road. An object is spotted on the road 450 ft ahead and th...

Questions