Question

A bowling ball weighing 10.0 N is dropped off the top of a 5.00 m tall building. After falling 1.00 m, the book’s kinetic energy is?
a. 10.0 J b. 5.00 J c. 40.0 J d. 50.0 J

Answer 1

Answer:

a

Explanation:

Potential energy (before the drop)= mgh

• m=mass=1kg
• g= 10N/kg
• h=5m

E.p = 1 × 5 × 10

E.p = 50J

This energy can also be stated as the internal energy. Internal Energy the sum of kinetic and potential energy.

At rest the internal enery was:

E.p+E.k=I.e

50 + 0 =I.e

So the internal energy is 50J

After it has fallen 1 metre, the internal energy is always the same 50J, but the potential and kinetic energy have been changed.

The new potential energy = mgh

m= 1kg

g= 10 N/kg

h= 5-1=4m

New E.p = 1 × 10 ×4= 40J

I.e = E.p + E.k

50 = 40 + E.k

E.k = 10 J

Answer : a