Dynamics Practice Test

1.

An object remains at rest unless acted upon by an unbalanced force. This is a statement of:

a) Newton’s First Law b) Newton’s Second Law c) Newton’s Third Law d) Law of Gravitation

2.

A 4 kg object experiences a net force of 10 N. What is its acceleration?

a) 1.5 m/s² b) 2.5 m/s² c) 4.0 m/s² d) 0.4 m/s²

3.

If object A exerts a force of 5 N on object B, what is the magnitude of the force object B exerts on A?

a) 10 N b) 0 N c) 5 N d) Depends on the masses

4.

Which of the following is a contact force?

a) Gravitational force b) Magnetic force c) Friction d) Electric force

5.

Which force opposes the motion of a sliding object?

a) Static friction b) Kinetic friction c) Tension d) Normal force

6.

Which force always acts perpendicular to a surface?

a) Weight b) Tension c) Normal force d) Friction

7.

What is the static friction force if an object remains stationary under a 20 N pulling force and does not move?

a) 0 N b) 10 N c) 20 N d) Depends on kinetic friction

8.

Which of the following is *not* needed to construct a free body diagram?

a) Object's mass b) All forces acting on the object c) Coordinate system d) Proportional arrows for forces

9.

In uniform circular motion, the net force is always directed:

a) Tangent to the circle b) Outward from the circle c) Toward the center d) Perpendicular to the axis

10.

If a 2 kg mass is whirled in a horizontal circle of radius 1.5 m at a speed of 3 m/s, what is the centripetal force?

a) 6 N b) 9 N c) 12 N d) 3 N

11.

What happens to the tension in a rope if the mass it supports is doubled, assuming no other changes?

a) It halves b) It doubles c) It stays the same d) It becomes zero

12.

A block is connected to a spring and oscillates horizontally. Which law describes the spring force?

a) Newton's First Law b) Hooke's Law c) Ohm's Law d) Coulomb's Law

13.

What is the restoring force of a spring that is compressed 0.1 m with a spring constant of 200 N/m?

a) 20 N b) 200 N c) 2 N d) 0.5 N

14.

Drag force increases with:

a) Mass b) Velocity c) Acceleration d) Time

15.

Which statement about equilibrium is correct?

a) Net force is nonzero b) Acceleration is constant c) Velocity is changing d) Net force is zero

16.

Which pair correctly illustrates Newton’s Third Law?

a) Gravity pulls on a rock; rock pulls on gravity b) Earth pulls on the moon; moon pulls on Earth c) Truck pushes on car; car slows down d) Engine accelerates train; track resists

17.

If an object is accelerating downward at 9.8 m/s², which force must be zero?

a) Gravity b) Tension c) Normal force d) Net force

18.

A box is pushed up a rough incline at constant speed. What can be said about the net force?

a) It points up the incline b) It points down the incline c) It is zero d) It is equal to friction

19.

Which of the following correctly shows the direction of drag force on a falling object?

a) Upward b) Downward c) Perpendicular to motion d) Zero

20.

Which component is always present in a free body diagram of a block sliding down a ramp?

a) Tension b) Friction c) Weight d) Normal force

21.

Two ice skaters push off from each other on a frictionless surface. Skater A has mass 60 kg and skater B has mass 40 kg. Who experiences greater acceleration?

a) Skater A b) Skater B c) Both experience the same acceleration d) Neither skater moves

22.

A 15 kg object is in equilibrium while suspended from two cables at angles. What must be true about the net force on the object?

a) Equal to the weight of the object b) Directed upward c) Directed horizontally d) Zero

23.

Which force is responsible for circular motion?

a) Gravitational force b) Frictional force c) Centripetal force d) Normal force

24.

Which situation demonstrates Newton’s First Law?

a) A ball rolling on a smooth surface continues in a straight line b) A car speeds up as it moves downhill c) A person pushes a wall and the wall pushes back d) A spring stretches with increasing force

25.

A car moves in a circle at constant speed. What happens to its velocity vector?

a) It stays constant b) It changes direction but not magnitude c) It changes magnitude but not direction d) It increases continuously

26.

A satellite orbits Earth in uniform circular motion. What provides the centripetal force?

a) Normal force b) Friction c) Gravity d) Tension

27.

An object is falling at terminal velocity. Which two forces are equal in magnitude?

a) Tension and normal force b) Gravity and drag c) Gravity and friction d) Normal force and drag

28.

A box is on a rough surface and not moving. Which force opposes the component of gravity down the incline?

a) Normal force b) Tension c) Static friction d) Kinetic friction

29.

A spring with spring constant 400 N/m is stretched 0.1 m. What is the force it exerts?

a) 4 N b) 40 N c) 0.25 N d) 0.4 N

30.

Which of the following best describes the direction of the net force acting on a car turning in a circular path at constant speed?

a) Tangent to the curve b) Opposite to the motion c) Perpendicular to the motion d) Toward the center of the curve

30 Questions – Mixed Conceptual & Calculations