Question

A baby carriage is sitting at the top of the hill that is 21 m high. The baby weighs 12n. The carriage has__________ energy. Calculate it.

Answer 1

Step-wise Solution with explanation:

Step1:

First, We know,

The total mechanical energy of an object or system is given by:

Emech=K+U

Where K is the kinetic energy of the object and U is the potential energy of the object. The carriage, sitting motionless at the top of the hill, has only potential energy in the form of gravitational potential energy.

Step2:

Then,

Gravitational potential energy is given by:

Ug=mgh

Where m is the mass of the object, g is the gravitational acceleration constant, and h is the height of the object above some specific reference point, in this case the ground 21m below.

Step3:

Now,

The weight of a stationary object at the surface of the earth is equal to the force of gravity acting on the object.

W=→Fg=mg

Step4:

We are given that the carriage weighs 12N, therefore mg=12N.

Ug=12N⋅21m

⇒Ug=252Nm=252J