Answer:
Explanation:
Given
mass of box 
speed of box 
distance moved by the box 
coefficient of kinetic friction 
Friction force 
Kinetic Energy of box will be utilize to overcome friction and rest is stored in spring in the form of elastic potential energy
<span> Use the Law of Cosines, where you have a triangle with included angle of 145 degrees and sides of 16 and 18. You are then solving the equation: </span>
<span>d^2 = 16^2 + 18^2 - 2(16)(18)cos(145) </span>
Answer:
36.87 km/h
Explanation:
Convert all the units in SI system
1 mile = 1609.34 m
d1 = 6 mi = 9656.04 m
t1 = 15 min = 15 x 60 = 900 s
d2 = 3 mi = 4828.02 m
t2 = 10 min = 10 x 60 = 600 s
d3 = 1 mi = 1609.34 m
t3 = 2 min = 2 x 60 = 120 s
d4 = 0.5 mi = 804.67 m
t4 = 0.5 min = 0.5 x 60 = 30 s
Total distance, d = d1 + d2 + d3 + d4
d = 9656.04 + 4828.02 + 1609.34 + 804.67 = 16898.07 m = 16.898 km
total time, t = t1 + t2 + t3 + t4
t = 900 + 600 + 120 + 30 = 1650 s = 0.4583 h
The ratio of the total distance covered to the total time taken is called average speed.
Average speed = 16.898 / 0.4583 = 36.87 km/h
20.4 years is 20.4/10.2 = 2 half-life cycles, which means a quarter of the starting mass or 15.2 g will remain after this time.
