IB Physics HL A.1 Kinematics Question Bank

Practise IB Physics HL A.1 by solving motion, projectile and drag problems with position, velocity and acceleration data.

Exam points

interpret position, velocity and acceleration graphs using gradients, areas and vector signs
select and apply constant-acceleration equations with signed quantities and SI units
resolve projectile components and analyse changing acceleration or terminal speed from data

Covered syllabus points

A.1.1—Position, velocity and acceleration A.1.2—Velocity and acceleration rates A.1.3—Displacement A.1.4—Distance and displacement A.1.5—Instantaneous and average values A.1.6—Uniform acceleration equations A.1.7—Uniform vs non-uniform acceleration A.1.8—Projectile components A.1.9—Fluid resistance on projectiles

[Maximum number: 7]

A student throws a ball towards a wall. The ball is released from a point 1.8 m above the ground and 8.0 m from the wall. The initial velocity of the ball makes an angle of $48^{\circ}$ with the horizontal. Air resistance is negligible.

The diagram shows the initial path of the ball. P is a point on the path.

Figure for Question A.1 Kinematics question 1 — IB Physics HL

(a)

Draw, on the diagram, an arrow to show

[ 2 ]

(i)

the velocity of the ball at P . Label this arrow v.

[ 1 ]

(ii)

the acceleration of the ball at P. Label this arrow a.

The ball takes 1.3 s to reach the wall.

[ 1 ]

(b)

Show that the initial speed of the ball is about $9 \mathrm{~ms}^{-1}$ .

[ 2 ]

horizontal velocity $v_{x}=\frac{8.0}{1.3} \|=6.2 \mathrm{~m} \mathrm{~s}^{-1} »$ $\text { " } \frac{v_{x}}{v}=\cos 48^{\circ} \Rightarrow \text { " } \| V=\frac{8.0}{1.3 \cos 48^{\circ}}=9.2 \text { " } \mathrm{m} \mathrm{~s}^{-1} \text { " }$

(c)

Determine the height above the ground at which the ball hits the wall.

[ 3 ]

initial vertical velocity $v_{y}=9.2 \sin 48^{\circ}$ « $=6.8 \mathrm{~m} \mathrm{~s}^{-1}$ »
$h=1.8+\left(9.2 \sin 48^{\circ} \times 1.3\right)-\frac{1}{2} \times 9.8 \times 1.3^{2}$

2.4 «m»

Marking guidance:

Award [2 max] for h=0.6 m - candidates have not taken the initial height of 1.8m into account.

Award [2 max] for h=19 m

Award [3] for BCA

[Maximum number: 2]

A toy rocket is made from a plastic bottle that contains some water.

Air is pumped into the vertical bottle until the pressure inside forces water and air out of the bottle. The bottle then travels vertically upwards.

Figure for Question A.1 Kinematics question 2 — IB Physics HL

The air-water mixture is called the propellant.
The variation with time of the vertical velocity of the bottle is shown.

The bottle reaches its highest point at time $T_{1}$ on the graph and returns to the ground at time $T_{2}$ . The bottle then bounces. The motion of the bottle after the bounce is shown as a dashed line.

Estimate the acceleration of the bottle when it is at its maximum height.

Attempt to calculate gradient of line at $t=1.2 \mathrm{~s}$

«-» 9.8 «m s ${ }^{-2}$ » (accept 9.6-10.0)

[Maximum number: 11]

A ball is released near the surface of the Moon at time t=0. The point of release is on a straight line between the centre of Earth and the centre of the Moon. The graph below shows the variation with time t of the displacement s of the ball from the point of release.

Figure for Question A.1 Kinematics question 3 — IB Physics HL

(a)

State the significance of the negative values of s.

[ 1 ]

(b)

Use the graph to

[ 6 ]

(i)

estimate the velocity of the ball at $t=0.80 \mathrm{~s}$ .

[ 3 ]

tangent drawn to curve at 0.80 s ;
correct calculation of gradient of tangent drawn;
$-1.3 \pm 0.1 \mathrm{~m} \mathrm{~s}^{-1}$ or $1.3 \pm 0.1 \mathrm{~m} \mathrm{~s}^{-1}$ downwards;
or
correct coordinates used from the graph; substitution into a correct equation;
$-1.3 \pm 0.1 \mathrm{~m} \mathrm{~s}^{-1}$ or $1.3 \pm 0.1 \mathrm{~m} \mathrm{~s}^{-1}$ downwards;

(ii)

calculate a value for the acceleration of free fall close to the surface of the Moon.

[ 3 ]

any correct method used;
correct reading from graph;
1.6 to $1.7 \mathrm{~m} \mathrm{~s}^{-2}$ ;

(c)

Calculate the speed of an identical ball when it falls 3.0 m from rest close to the surface of Earth. Ignore air resistance.

[ 1 ]

$\quad 7.7 \mathrm{~m} \mathrm{~s}^{-1}$ ;

(d)

Sketch, on the graph, the variation with time t of the displacement s from the point of release of the ball when the ball is dropped close to the surface of Earth.

(For this sketch take the direction towards the Earth as being negative.)

[ 3 ]

curve permanently below Moon curve; smooth parabola; (judge by eye)
line passing through $\mathrm{s}=-3.00 \mathrm{~m}, \mathrm{t}=0.78 \mathrm{~s}$ or $\mathrm{s}=-3.50 \mathrm{~m}, \mathrm{t}=0.84 \mathrm{~s}( \pm 1 \mathrm{~mm})$ ;

Figure for Answer to Question (d) — IB Physics HL

Part 2 Radioactivity

All question bank results loaded

Covered syllabus points

A.1 Kinematics question 1

Question (a)

Question (i)

Question (ii)

Question (b)

Question (c)

A.1 Kinematics question 2

A.1 Kinematics question 3

Question (a)

Question (b)

Question (i)

Question (ii)

Question (c)

Question (d)