Answer:
V1 =8.1 m/s
Explanation:
height at highest point (h2) = 4.1 m
height at lowest point (h1) = 0.8 m
acceleration due to gravity (g) = 9.8 m/s^{2}
from conservation of energy, the total energy at the lowest point will be the same as the total energy at the highest point. therefore
mgh1 + 
= mgh2 + 
where
- speed at highest point = V2
- speed at lowest point = V1
- mass of the girl and swing = m
- at the highest point, the speed is minimum (V1 = 0)
- at the lowest point the speed is maximum (V2 is the maximum speed)
- therefore the equation becomes mgh1 + = mgh2
m(gh1 + 
) = m(gh2)
gh1 + = gh2
V1 = 
now we can substitute all required values into the equation above.
V1 = 
V1 = 
V1 =8.1 m/s
Answer:
Option D.
Explanation:
The correct answer is Option D.
The shrinkage of the bridge material is because of thermal contraction.
Thermal contraction and thermal expansion are the phenomena of the bridge material which takes place due to the change in temperature of the atmosphere.
When the temperature of the surrounding increases expansion of the bridge material takes place and when temperature decreases the contraction of the material takes place.
This phenomenon sometimes damages the structure because due to continuous expansion and contraction of materials strength of the bridge decreases.
This statement is true. The angle that the Sun's rays strike a region of Earth determines the amount of heat transferred. For example, as you seen on TV, a laser pointing at an object and that specific angle that the rays of the laser pointed at was being melted. Same goes for the relationship between the Sun's rays and the Earth because it has the same energy that is being emitted per second.
Because heat keeps us warm and water hydrates the planet i guess?????
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Answer:
5.3 seconds
Explanation:
Vx = Vx0 + Ax .T
A= de-acceleration
Vx =0 final at rest velocity
Vx0 = initial velocity
T= time to bring the object to a stop
therefore
0 = 52 m/s - (9.8 m/s^2) . T
-52 m/s/ -9.8 m/sec^2 =T
5.3 seconds= T
