<h2>
Kinetic energy just before hitting the floor is 324.57 J</h2>
Explanation:
Weight of volleyball player = 650 N
That is
Mass x Acceleration due to gravity = 650
Mass x 9.81 = 650
Mass = 66.26 kg
We also have equation of motion v² = u² + 2as
Initial velocity, u = 0 m/s
Acceleration, a = 9.81 m/s²
Final velocity, v = ?
Displacement, s = 0.5 m
Substituting
v² = u² + 2as
v² = 0² + 2 x 9.81 x 0.5
v = 3.13 m/s
Velocity with which he lands on ground is 3.13 m/s
We have kinetic energy = 0.5 x Mass x Velocity²
Substituting
Kinetic energy = 0.5 x 66.26 x 3.13²
Kinetic energy = 324.57 J
Kinetic energy just before hitting the floor is 324.57 J
Answer:
1.635×10^-3m
Explanation:
Young modulus is the ratio of the tensile stress of a material to its tensile strain.
Young modulus = Tensile stress/tensile strain
Tensile stress = Force/Area
Given force = 130N
Area = Πr² = Π×(1.55×10^-3)²
Area = 4.87×10^-6m²
Tensile stress = 130/4.87×10^-6 = 8.39×10^7N/m²
Tensile strain = extension/original length
Tensile strain = e/3.9
Substituting in the young modulus formula given young modulus to be 2×10¹¹N/m²
2×10¹¹N/m² = 8.39×10^7/{e/3.9)}
2×10¹¹ = (8.39×10^7×3.9)/e
2×10¹¹e = 3.27×10^8
e = 3.27×10^8/2×10¹¹
e = 1.635×10^-3m
The stretch of the steel wire will be
1.635×10^-3m
Answer:
The gravitational potential energy between two particles, if the distance between them is halved, is multiplied by 4 (option c).
Explanation:
The gravitational force is the force of mutual attraction that two objects with mass experience.
The Law of Universal Gravitation enunciated by Newton says that every material particle attracts any other material particle with a force directly proportional to the product of their masses and inversely proportional to the square of the distance that separates them. Mathematically this is expressed as:
where m1 and m2 are the masses of the objects, r the distance between them and G a universal constant that receives the name of constant of gravitation.
If the distance between two particles is reduced by half, then, where F' is the new value of the gravitational force:
F'=4*F
<u><em>
The gravitational potential energy between two particles, if the distance between them is halved, is multiplied by 4 (option c).</em></u>
To add vectors we can use the head to tail method (Figure 1).
Place the tail of one vector at the tip of the other vector.
Draw an arrow from the tail of the first vector to the tip of the second vector. This new vector is the sum of the first two vectors.
