Answer:
13 km/h
Explanation:
Average speed = distance/time
Let the total distance and total time taken for the whole trip be d km and t hours respectively
Average speed for the whole trip = 82 km/h
d = 82t
The distance covered in the first half = d1/2
Time taken = t/2
Average speed = 69 km/h
69 = d1/2 ÷ t/2
d1 = 69t
The distance covered in the second half = d2/2
Time taken = t/2
Let the average sly for the see half be A
A = d2/2 ÷ t/2
d2 = At
d = d1 + d2
82t = 69t + At
At = 82t - 69t
At = 13t
A = 13t/t = 13 km/h
Answer:
0.41
Explanation:
given,
mass of the car, m = 2290 Kg
initial speed = 10.5 m/s
mass of another car, M = 2780 Kg
distance moved = 2.80 m
coefficient of friction = ?
conservation of energy
m u = (M + m) V
2290 x 10.5 = (2290 + 2780) V
V = 4.74 m/s
using equation of motion
v² = u² + 2 a s
4.74² = 2 x a x 2.8
a = 4.02 m/s²
now using equation
a = μ g
4.02 = μ x 9.8
μ = 0.41
Less than 7, Ph of 7 is neutral Acid Rain would be between 4 and 0.
