Topic 1.2: Forces and Momentum Questions

A 0.45 kg ball experiences a single net force of 6.0 N.

Calculate the magnitude of its acceleration.

A single force of 200 N acts on a trolley at 52° above the horizontal.

Calculate the horizontal and vertical components of this force.

(cos 52° = 0.62, sin 52° = 0.79)

A cork floats at rest, partly submerged, on the surface of still water.

Identify the two forces acting on the cork and state the relationship between their magnitudes.

State Newton's first law of motion.

A satellite moves in a circular orbit around a planet at a constant speed.

State the direction of the net force acting on the satellite, and state why the satellite is accelerating even though its speed does not change.

State the condition that must be met for the total momentum of a system of objects to be conserved during a collision.

A 0.45 kg ball travelling at 14 m s⁻¹ is caught by a fielder and brought to rest in 0.060 s.

Determine the magnitude of the average force the fielder's hands exert on the ball.

State what is meant by an object being in translational equilibrium.

State what is meant by the momentum of an object, and explain why momentum is a vector quantity.

A 2.5 kg block sliding on a frictionless surface speeds up from 3.0 m s⁻¹ to 11 m s⁻¹ along a straight line.

Calculate the impulse delivered to the block.

State what is meant by the static friction force acting on an object.

A solid brass cylinder of volume 4.0 × 10⁻⁴ m³ is fully submerged in water of density 1.0 × 10³ kg m⁻³ (g = 9.8 N kg⁻¹).

Calculate the buoyancy force on the cylinder.

State what is meant by the terminal velocity of an object falling through a fluid.

State Archimedes' principle.

Two identical cars take the same flat bend.

Car X takes it at 12 m s⁻¹ and car Y takes it at 36 m s⁻¹.

Deduce the ratio of the centripetal force needed by car Y to that needed by car X, and comment on why fast bends are dangerous.

A 3.0 kg block is driven up a smooth vertical wall by a constant force of 45 N pushing straight up.

Taking g = 9.8 m s⁻², determine the block's acceleration up the wall.

A crate is dragged at constant velocity across a level floor by a rope held at 25° above the horizontal with a tension of 90 N.

Explain, with reference to equilibrium, why the friction force on the crate equals the horizontal component of the tension, and calculate that friction force.

(cos 25° = 0.91)

Two boxes sit on a smooth floor: a 5.0 kg box behind a 3.0 kg box, joined by a light string.

A horizontal force of 24 N pulls the 3.0 kg front box.

Calculate the acceleration of the pair and the tension in the connecting string.

A heavy lantern of weight 120 N hangs from a point where two ropes meet.

Each rope runs up to a wall and makes an angle of 40° above the horizontal, and the arrangement is symmetric.

Show that the tension in each rope is about 93 N.

(sin 40° = 0.64)

A box rests on a rough ramp tilted at 25° to the horizontal and stays still.