Free Work MCQs with Answers

• A. 0 degrees
• B. 45 degrees
• C. 90 degrees
• D. 180 degrees

Explanation: Work is the scalar product Fd cos theta, and cos 90 degrees is zero, so a force perpendicular to the displacement does no work.

• A. equal to mgh
• B. zero
• C. equal to the weight times the distance walked
• D. negative

Explanation: The upward force supporting the suitcase is perpendicular to the horizontal displacement, so the work done against gravity is zero.

• A. a force acts on it
• B. a force acts and the body moves with a component of displacement along the force
• C. the body is at rest
• D. the body has energy

Explanation: Work is the dot product of force and displacement, so a porter standing still holding a heavy suitcase does no work on it however tiring…

• A. 200 J
• B. 100 J
• C. 173 J
• D. 0 J

Explanation: Only the component of force along the displacement counts, so the work is 50 multiplied by 4 multiplied by cos 60, which is 200 multiplied…

• A. maximum
• B. zero
• C. equal to the kinetic energy
• D. negative

Explanation: The force points to the centre while the displacement is along the tangent, so the two are perpendicular and the dot product is zero at…

• A. acts in the same direction as the displacement
• B. has a component opposite to the displacement, so it removes energy from the body
• C. does no work at all
• D. acts at right angles to the displacement

Explanation: Friction and air resistance always oppose the motion and therefore always do negative work, reducing the kinetic energy.

• A. 3.5 x 10^-3 J
• B. 3.5 x 10^4 J
• C. 3.5 x 10^6 J
• D. 3.5 x 10^9 J

Explanation: With no friction, the work done in raising the elevator equals force times vertical distance: W = Fd = (3.5 x 10^-6 N)(1000 m) = 3.5 x…

• A. Work
• B. Energy
• C. Power
• D. Momentum

Explanation: Energy is defined as the capacity of a body or system to do work, and it is measured in joules (J).

• A. It's works equals the change in the kinetic energy of the particle.
• B. It's obeys Newton's second law
• C. It's obeys Newton's third law
• D. It work depends on the end points of every motion, not on the path between.

Explanation: A conservative force does work that depends only on the initial and final positions, not on the path taken between them.

• A. at any instant
• B. averagely
• C. during its operation
• D. during one cycle

Explanation: On a pressure-volume diagram, the area enclosed by a complete cycle equals the net work done, because work is found from the integral of…

• A. Maximum work
• B. Minimum work
• C. Negative work
• D. No work

Explanation: Centripetal force acts radially inward, while instantaneous displacement is tangential to the circle.

• A. Stiffness
• B. Toughness
• C. Extension
• D. Deformation

Explanation: Deformation is any change in a body's shape or dimensions caused by an applied force, including changes in length, area or volume.

• A. Brittle
• B. Ductile
• C. Amorphous
• D. Polymers

Explanation: A ductile material can undergo substantial plastic deformation, meaning permanent deformation, before it fractures.

• A. 2 x 10^8 Nm-2
• B. 5 x 10^6 Nm-2
• C. 0.5 x 10^-6 Nm-2
• D. 0.2 x 10^-6Nm-2

Explanation: Young's modulus is Y = FL/(AΔL). Converting 2 cm^2 to 2 x 10^-4 m^2, Y = (10 N)(1 m)/[(2 x 10^-4 m^2)(0.01 m)] = 5 x 10^6 N m^-2.

• A. Nm-2
• B. Jm-2
• C. Nm-1
• D. Being a number it has no unit.

Explanation: Modulus of elasticity is stress divided by strain; strain has no unit, so its unit is the unit of stress, N m^-2, also called the pascal.

• A. non-conservative force
• B. conservative force
• C. both A and B
• D. none of these

Explanation: Rocket thrust is produced by ejecting gases and depends on the changing mass and interaction of the rocket with its exhaust, so it is…

• A. area
• B. work done
• C. power
• D. none of these

Explanation: Work is the integral of force with respect to displacement, so the area under a force-displacement graph gives work done, measured in…

• A. torque
• B. angular momentum
• C. linear momentum
• D. power

Explanation: Work has dimensions force x distance, giving [M L2 T-2]. Torque is also force x perpendicular distance, so it has the same dimensions…

• A. frictional force
• B. gravitational force
• C. elastic force
• D. centripetal force

Explanation: Work is W = Fd cos θ. Centripetal force points toward the centre while instantaneous displacement is tangential, so θ = 90° and W = Fd cos…

• A. electric field
• B. conservative field
• C. electromagnetic field
• D. gravitational field

Explanation: A conservative field has zero net work around every closed path, so the work depends only on the initial and final positions.