Conservation of Energy — Practice Quiz

Question 1

A 1 kg ball is dropped from 10 m height. Speed just before hitting ground (g = 10):

Accepted Answer

14 m/s

Answer

10 m/s

Answer

20 m/s

Answer

100 m/s

Question 2

A pendulum bob of mass m starts at height h. Max speed (at lowest point):

Accepted Answer

√(2gh)

Answer

√(gh)

Answer

gh

Answer

2gh

Question 3

When mechanical energy is NOT conserved:

Accepted Answer

Non-conservative forces like friction act

Answer

No external forces

Answer

Only conservative forces

Answer

Body is at rest

Question 4

A block slides down a frictionless inclined plane from height 5 m. Speed at bottom:

Accepted Answer

≈ 10 m/s

Answer

≈ 7 m/s

Answer

≈ 5 m/s

Answer

≈ 14 m/s

Question 5

Energy is conserved in:

Accepted Answer

All collisions if you include heat/deformation

Answer

Only elastic collisions

Answer

Only mechanical processes

Answer

Only in vacuum