Answer:
Explanation:
speed of motor (N)=1500 rpm
power=4 hp = 
=2.9828 KW
service factor(k)= 2.75
now,
torque rating
The contractor definitely breached the contract
Answer:
Negotiated speed should be lower. Perception/reaction time is too less than design values.
Explanation:
Given:
- The claimed safe speed V_1 = 65 mi/h
- Sight distance D = 510 ft
- The practical deceleration a = 11.2 ft/s ... according to standards
Find:
Assuming practical stopping distance, comment on the student whether the claim is correct or not
Solution:
- Calculate the practical stopping distance:
d = V_1^2 / 2*a
d = ( 65 * 1.46 )^2 / 2*11.2 = 402.054 ft
- Solve for reaction distance d_r is as follows:
d_r = D - d = 510 - 402.054 = 107.945 ft
- The perception/time reaction is:
t_r = d_r/V_1 = 107.945 / 94.9
t_r = 1.17 sec
Answer: The perception/reaction time t_r = 1.17 s is well below the t = 2.3 s.
Hence, the safe speed should be lower.
