Assertion and reason

Exercise and reference answers

Questions

1. Reason

   The work it does depends on the path, and is not zero round a loop.

   Verdict

   Both are true; the reason explains the assertion.

   Assertion

   Friction is not a conservative force.

2. Reason

   Gravity is conservative, and conservative forces admit such a function.

   Verdict

   Both are true; the reason explains the assertion.

   Assertion

   A potential energy can be defined for gravity.

3. Reason

   Net work equals the change in kinetic energy.

   Verdict

   Both are true; the reason explains the assertion.

   Assertion

   A body's speed changes when net work is done on it.

4. Reason

   Work is done whenever a force acts through a displacement.

   Verdict

   The assertion is false and the reason is true.

   Assertion

   Every force is conservative.

Explanation