Answer:
P.E = 980 J
Explanation:
Given,
The mass of the rock, m = 1 Kg
The height of the rock from the ground, h = 100 m
The acceleration due to gravity, a = 9.8 m/s²
The gravitational potential energy of the stone is given by the formula
P.E = mgh joules
Substituting the given values in the above equation,
P.E = 1 x 100 x 9.8
= 980 J
Hence, the gravitational potential energy of the stone is, P.E = 980 J
Answer:
The ice will melt and her hand will get cold
Explanation:
Answer: 23 hours 56 minutes 4.091 seconds
Explanation: The time it takes Earth to rotate so the sun appears in the same position in the sky, known as a solar day, is 24 hours. However, the time it takes Earth to complete one full rotation on its axis with respect to distant stars is actually 23 hours 56 minutes 4.091 seconds, known as a sidereal day.
Answer:
A. when the mass has a displacement of zero
Explanation:
The velocity of a mass on a spring can be calculated by using the law of conservation of energy. In fact, the total energy of the mass-spring system is equal to the sum of the elastic potential energy (U) of the spring and the kinetic energy (K) of the mass:

where
k is the spring constant
x is the displacement of the mass with respect to the equilibrium position of the spring
m is the mass
v is the velocity of the mass
Since the total energy E must remain constant, we can notice the following:
- When the displacement is zero (x=0), the velocity must be maximum, because U=0 so K is maximum
- When the displacement is maximum, the velocity must be minimum (zero), because U is maximum and K=0
Based on these observations, we can conclude that the velocity of the mass is at its maximum value when the displacement is zero, so the correct option is A.