2. A baby carriage is sitting at the top of a hill that is 21 m high. The carriage with the baby has a mass of 12 kg. The carriage has energy. Calculate it.
The total mechanical energy of an object is given by,
E_{mech} = K +UE
mech
=K+U
Where K is the Kinetic Energy and U is the Potential Energy.
Because the carriage is sitting motionless at the top of the hill it will only have the potential energy in the form of gravitational potential energy.
Gravitational potential energy is given by:
U_g = m*g*hU
g
=m∗g∗h ⇒ Equation (1)
The weight of a stationary object on the surface of the earth is equal to the gravitational force acting on the object.
Answers & Comments
Answer:
Given,
Height (h) = 21 m
Weight (W) = 12 N
Where,
To Find,
The Gravitational Potential Energy.
Solution,
We know that,
The total mechanical energy of an object is given by,
E_{mech} = K +UE
mech
=K+U
Where K is the Kinetic Energy and U is the Potential Energy.
Because the carriage is sitting motionless at the top of the hill it will only have the potential energy in the form of gravitational potential energy.
Gravitational potential energy is given by:
U_g = m*g*hU
g
=m∗g∗h ⇒ Equation (1)
The weight of a stationary object on the surface of the earth is equal to the gravitational force acting on the object.
W = F_g = m*gW=F
g
=m∗g
Substituting the given values in equation (1)
U_g = 12*21U
g
=12∗21
U_g = 252NmU
g
=252Nm
U_g = 252JU
g
=252J
Therefore,
The Gravitational Potential Energy is 252 J.