Question

You throw a hammer from a second floor window. Check all that apply for the duration of its flight. Neglect air resistance.

Group of answer choices

The angular momentum of the hammer is conserved

The linear momentum of the hammer is conserved

The total mechanical energy of the hammer is conserved

Every point of the hammer is flying on a parabola

There is one point of the hammer that is flying on a parabola

There are no points that fly on a parabola

The net force on the hammer is zero

The net torque on the hammer is zero

Answer 1

The angular momentum of the hammer is conserved

Reason - Force of gravity acts on the center of mass of hammer and there is no external torque acting on it during the flight duration, so angular momentum is conserved.

The linear momentum of the hammer is conserved

Reason - Force of gravity acts on the hammer during the flight duration, so linear momentum in vertical direction is not conserved.

The total mechanical energy of the hammer is conserved

Reason - No viscous, drag or dissipative forces act. So the total mechanical energy of the system is conserved.

Every point of the hammer is flying on a parabola

Reason - Only the center of mass of the body undergoes parabolic path during flight. No all points do the same. For example the extremes of hammer would be in rotation motion with respect to the center of mass

There is one point of the hammer that is flying on a parabola.

Reason - The center of mass follows the parabolic path which is the resultant of constant velocity motion in horizontal direction and accelerated motion in vertical direction.

There are no points that fly on a parabola

Reason - As stated previously, the center of mass fly in a parabolic path.

The net force on the hammer is zero

Reason - Force of gravity acts on hammer. So net force is not zero.

The net torque on the hammer is zero

Reason - Gravity acts on center of mass, thus, no torque is generated.