Answer:
Potential energy of spring = 24 Joules.
Explanation:
Given the following data;
Spring constant = 85N/m
Extension, e = 0.75m
Mass = 25kg
To find the potential energy of a spring
Potential energy of a spring is given by the formula;
P.E = ½ke²
Substituting into the equation, we have
P.E = ½*85*0.75²
P.E = 42.5 * 0.5625
P.E = 23.91 ≈ 24 Joules
P.E = 24 Joules
Answer:
Explanation:
- We have to make a hollow sphere of inner radius and outer radius .
Then the mass of the material required to make such a sphere would be calculated as:
Total volume of the spherical shell:
And the volume of the hollow space in the sphere:
Therefore the net volume of material required to make the sphere:
- Now let the density of the of the material be .
<u>Then the mass of the material used is:</u>
The first answer should be correct if not then the second one
The correct answer is:
D. Extrusive rocks.
The explanation:
when extrusive igneous rocks form when magma reaches the Earth's surface a volcano and cools quickly. Most extrusive (volcanic) rocks have small crystals. Examples include basalt, rhyolite, andesite, and obsidian.
Answer:
Vf = 15 m/s
Explanation:
First we consider the upward motion of ball to find the height reached by the ball. Using 3rd equation of motion:
2gh = Vf² - Vi²
where,
g = acceleration due to gravity = -9.8 m/s² (negative sign for upward motion)
h = height =?
Vf = Final Velocity = 0 m/s (Since, ball momentarily stops at highest point)
Vi = Initial Velocity = 15 m/s
Therefore,
2(-9.8 m/s²)h = (0 m/s)² - (15 m/s)²
h = (-225 m²/s²)/(-19.6 m/s²)
h = 11.47 m
Now, we consider downward motion:
2gh = Vf² - Vi²
where,
g = acceleration due to gravity = 9.8 m/s²
h = height = 11.47 m
Vf = Final Velocity = ?
Vi = Initial Velocity = 0 m/s
Therefore,
2(9.8 m/s²)(11.47 m) = Vf² - (0 m/s)²
Vf = √(224.812 m²/s²)
<u>Vf = 15 m/s</u>