Fill in the blank: The work is said to be positive if the angle between force and displacement is ___ (angle less than  90°).

Acute

What does negative work indicate about the energy supplied to the system?

Negative work indicates that the force is extracting energy from the system.

True or False: The work done by a force is independent of the frame of reference.

False. Work done by a force depends on the frame of reference.

What does the area under a force versus displacement graph represent?

The area under the graph represents the work done.

Riddle: I can stretch and compress, but I'm not a muscle. What am I?

A spring

What does the Work-Energy Theorem state about the sum of work done by all forces on a particle?

The sum of the work done by all forces is equal to the change in its kinetic energy.

Fill in the blank: A conservative force does work that is ___ of the path taken.

Independent

How is the conservative force related to potential energy?

The conservative force is defined as the negative gradient of the potential energy.

What is the condition for mechanical energy conservation in a system?

The total mechanical energy remains constant if internal forces are conservative and external forces do no work.

True or False: The work done by external forces can alter the total mechanical energy of a system.

True. External forces can do work and change the total mechanical energy.

What is the coefficient of restitution for perfectly elastic collisions?

The coefficient of restitution is 1 for perfectly elastic collisions.

In a head-on elastic collision, what happens to the velocities of two bodies of equal mass?

They interchange their velocities.

Fill in the blank: For a perfectly inelastic collision, the kinetic energy of the system is ___ conserved.

Not

What defines a non-conservative force?

The work done by a non-conservative force is path dependent and non-zero for a closed path.

True or False: The potential energy curve can indicate stable and unstable equilibrium positions.

True. The potential energy curve helps identify stable and unstable equilibrium positions.

What happens to the potential energy when the work done by a conservative force is negative?

The potential energy of the system increases.

Fill in the blank: The principle of conservation of mechanical energy states that ___ + ___ = constant.

Kinetic energy + potential energy

What is the significance of the slope of a potential energy curve?

The negative of the slope of the potential energy curve is equal to the conservative force.

Riddle: I can be the result of mass and velocity, but I’m not always conserved. What am I?

Kinetic energy

Fill in the blank: The instantaneous power is given by the product of ___ and ___ at that instant.

Applied force and instantaneous velocity

What happens during a collision with respect to the interaction forces before and after the collision?

Interaction forces are zero before and after the collision, but large during the collision.