Becuase Gravity. The Earthp pulls you down, you do not pull the earth.
<span>No, because the truck applies more pressure than the bridge can support.</span>
Answer: 24.7 km/h
Explanation:
1) Average speed definition and formula
The average speed is the total distance run divided by the time elapsed:
S = distance / time
2) Distance 1 = 67 km
3) Distance 2 = 81 km
4) Total distance traveled = 67 km + 81 km = 148 km
5) time 1 = 1 hour
6) time 2 = 5 hours
7) total time = time 1 + time 2 = 1 h + 5 h = 6 h
8) Average speed:
S = 148 km / 6 h = 24.7 km/h
Answer: The force constant k is 10600 kg/s^2
Step by step:
Use the law of energy conservation. When the elevator hits the spring, it has a certain kinetic and a potential energy. When the elevator reaches the point of still stand the kinetic and potential energies have been transformed to work performed by the elevator in the form of friction (brake clamp) and loading the spring.
Let us define the vertical height axis as having two points: h=2m at the point of elevator hitting the spring, and h=0m at the point of stopping.
The total energy at the point h=2m is:
The total energy at the point h=0m is:
The two Energy values are to be equal (by law of energy conservation), which allows us to determine the only unknown, namely the force constant k: