Answer:
7.74m/s
Explanation:
Mass = 35.9g = 0.0359kg
A = 39.5cm = 0.395m
K = 18.4N/m
At equilibrium position, there's total conservation of energy.
Total energy = kinetic energy + potential energy
Total Energy = K.E + P.E
½KA² = ½mv² + ½kx²
½KA² = ½(mv² + kx²)
KA² = mv² + kx²
Collect like terms
KA² - Kx² = mv²
K(A² - x²) = mv²
V² = k/m (A² - x²)
V = √(K/m (A² - x²) )
note x = ½A
V = √(k/m (A² - (½A)²)
V = √(k/m (A² - A²/4))
Resolve the fraction between A.
V = √(¾. K/m. A² )
V = √(¾ * (18.4/0.0359)*(0.395)²)
V = √(0.75 * 512.53 * 0.156)
V = √(59.966)
V = 7.74m/s
Average Velocity=Total Distance/Total Time


Answer:

Explanation:
Since the hoop is rolling on the floor so its total kinetic energy is given as

now for pure rolling condition we will have

also we have

now we will have


now by work energy theorem we can say



now solve for final speed

Answer: b) The velocity vector is perpendicular to the acceleration vector; the acceleration vector is parallel to the net force vector.
Explanation: A change in velocity creates an acceleration. As the object rotates through the circular path it is constantly changing direction, and hence accelerating, which causes a constant force to act upon the object. This Force acts towards the center of curvature, directly toward the axis of rotation in a direction parallel to the acceleration of the body along the path. Because the object is moving perpendicular to the force, the path followed by the object is a circular one. Hence the velocity of the object is perpendicular to the acceleration.
Answer:
Part a)

Part b)

Part c)

Explanation:
As we know that 5000 kg African elephant requires 70,000 Cal for basic needs per day
so we will have


so we have energy required per kg


Part a)
now we know that per kg the energy required will be same
so we have mass of the human is 68 kg
so energy required per day is given as


Part b)
Resting power is the rate of energy in Joule required per sec
so it is given as


Part c)
resting power given in the book is

so this is less than the power given

