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IB Physics HL A.2 Forces and Momentum Question Bank

Practise IB Physics HL A.2 by solving force, momentum, impulse and circular-motion problems across the shared evidence set.

Syllabus
First assessment 2025
Course
Physics HL
Level
HL

Exam points

  • draw free-body diagrams, resolve forces and apply Newton’s laws to equilibrium or acceleration
  • calculate friction, tension, elastic, drag, buoyant or field forces from a stated model
  • conserve signed momentum and use impulse, collisions, explosions or centripetal relations with correct units

Covered syllabus points

A.2.1—Newton’s three laws of motionA.2.2—Forces as interactions between bodiesA.2.3—Free-body diagramsA.2.4—Resultant force from diagramsA.2.5—Contact forcesA.2.6—Normal forceA.2.7—Frictional forceA.2.8—TensionA.2.9—Hooke’s law restoring forceA.2.10—Viscous dragA.2.11—BuoyancyA.2.12—Field forcesA.2.13—WeightA.2.14—Electric force FeA.2.15—Magnetic force FmA.2.16—Linear momentum conservationA.2.17—ImpulseA.2.18—Impulse-momentum changeA.2.19—Newton’s second law formsA.2.20—Elastic and inelastic collisionsA.2.21—ExplosionsA.2.22—Collision energyA.2.23—Centripetal accelerationA.2.24—Centripetal forceA.2.25—Direction change in circular motionA.2.26—Angular and linear speed

A.2 Forces and momentum question 1

[Maximum number: 7]

This question is about the forces on a skier.

A skier is pulled up a hill by a rope at a steady velocity. The hill makes an angle of 12∘12^{\circ} with the horizontal. The mass of the skier and skis is 73 kg . The diagram below shows three of the forces acting on the skier.

Figure for Question A.2 Forces and momentum question 1 — IB Physics HL

Question (a)

(a)

On the diagram, draw and label one other force acting on the skier.

[ 1 ]

Question (b)

(b)

Calculate the magnitude of the normal reaction acting on the skier.

[ 2 ]

Question (c)

(c)

The total frictional force acting is 65 N . Determine the tension in the rope.

[ 2 ]

Question (d)

(d)

Explain, using Newton's first law of motion, why the resultant force on the skier must be zero.

[ 2 ]

A.2 Forces and momentum question 2

[Maximum number: 15]

A girl on a sledge is moving down a snow slope at a uniform speed.

Figure for Question A.2 Forces and momentum question 2 — IB Physics HL

Question (a)

(a)

Draw the free-body diagram for the sledge at the position shown on the snow slope.

[ 2 ]

Question (b)

(b)

After leaving the snow slope, the girl on the sledge moves over a horizontal region of snow. Explain, with reference to the physical origin of the forces, why the vertical forces on the girl must be in equilibrium as she moves over the horizontal region.

[ 3 ]

Question (c)

(c)

When the sledge is moving on the horizontal region of the snow, the girl jumps off the sledge. The girl has no horizontal velocity after the jump. The velocity of the sledge immediately after the girl jumps off is 4.2 m s−14.2 \mathrm{~m} \mathrm{~s}^{-1}. The mass of the girl is 55 kg and the mass of the sledge is 5.5 kg . Calculate the speed of the sledge immediately before the girl jumps from it.

[ 2 ]

Question (d)

(d)

The girl chooses to jump so that she lands on loosely-packed snow rather than frozen ice. Outline why she chooses to land on the snow.

[ 3 ]

Question (e)

(e)

The sledge, without the girl on it, now travels up a snow slope that makes an angle of 6.5∘6.5^{\circ} to the horizontal. At the start of the slope, the speed of the sledge is 4.2 m s−14.2 \mathrm{~m} \mathrm{~s}^{-1}. The coefficient of dynamic friction of the sledge on the snow is 0.11 .

[ 3 ]

Question (i)

(i)

Show that the acceleration of the sledge is about −2 m s−2-2 \mathrm{~m} \mathrm{~s}^{-2}.

[ 3 ]

Question (f)

(f)

The coefficient of static friction between the sledge and the snow is 0.14 . Outline, with a calculation, the subsequent motion of the sledge.

[ 2 ]
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